Wow, a lot of stuff in a short amount of time!
Before I start with the hard stuff, let me start with the nice stuff: stay put if that matters to you. I am extremely jealous and would love to live in SD -- was just never willing to pay the $$$ to do so. So if that's your priority, do it. And congrats on the big salary and on your willingness to change.
Also: no point kicking yourself for stupid past decisions. There are many of us who chased high incomes because we wanted All The Things, and it took longer than it should have to figure out that all that stuff doesn't actually make you happy in the end. Ask me how I know. The important thing is that you are figuring this out, and you're trying to make changes that prioritize your family and your future and your health.
Now. . . .
Someone above said the most important thing: there is no magic pill. You have ADD'd yourself into a lot of fun, flashy stuff, and now you're looking at ADD'ing yourself into some sort of quick fix. But quick fixes don't work. Sure, there are things you can do as an immediate cash influx or to cut expenses. But it took you a lot of years to build your current habits and current debt levels, so you need to expect it to take a lot of years to break those habits and dig your way out. Selling toys and cabin is a great start, but it's just that: a start. I think you've already figured this out by reviewing your CC statements. It's what you do month-in, month-out from now that will decide your long-term success or failure.
Cars: Please challenge your thinking on how much money you actually make on them. For each car, start with the purchase price and date and selling price and date. Subtract the former from the latter -- looks like a lot of $$, yes? Now take your insurance, registration, maintenance, sales tax, title transfer costs, gas costs, and other carrying costs; add all those up and subtract from the first profit number to get to your actual profit over that period. Now: assume you took that purchase money and invested in some low-cost index fund or ETF (e.g., VTSAX) on the same day you bought the car -- figure out the share price on that day and calculate how many shares your purchase money would have gotten you. Now calculate how much those shares would be worth on the day you sold the car. How does that growth compare to the profit you got from the car? I bet you that overall, you'll find you'd have come out ahead if you had just invested the $$ in the market in the first place.* Remember, it's not just the profit you make, it's the opportunity cost of not putting that $$ somewhere else instead.
ADU: I am very, very against the ADU simply because of the eggs-in-basket issue. You don't choose to put your money elsewhere because that other option is going to get you a better return than the ADU, just like you don't maintain a diversified portfolio because it will get you the best returns. You do it as a way of protecting your downside. You do it because if you have so much of your net worth tied up in a single piece of property, you are completely, 100% fucked if something happened to that property. What happens if you have an earthquake that makes your property uninhabitable and unsellable? Most of your value is in the land, and home insurance covers only structures. So if that land itself becomes unreachable/unlivable, all that $$ is gone. Or what if we have a major recession that kills the SD real estate market because people can't afford those prices anymore? You're still stuck with the big mortgage and the ADU investment, even if you can't rent either out to save your life. Sure, maybe those sorts of things are very unlikely to happen. But bad shit happens all the time, and sometimes it happens to you.** The best thing you can do for your family is make sure that your entire future doesn't get fucked when it's your turn for the bad luck.
Side note: if you had $5M in investments, I'd be telling you to go for the ADU full steam ahead. Because that $5M will cover you even if the ADU goes into the total shitter. But you don't. So I'm not saying never -- just not now. Build up your other assets that are NOT tied to that one teensy piece of land first.
Net worth: your net worth is entirely useless in getting you set for retirement. For retirement planning, count on only what you're willing to sell. If your dream retirement involves staying put in your current location, then you can't count the value of your house in your retirement planning.
To put all of that in a slightly different way: almost everything you list in your "asset" list is in fact a consumption item, not an investment. You have an almost $1M lake house because you enjoy it. If you were looking at it as an investment -- $1500/mo for only part of the year, on a $900K value? -- it would be a royally shitty one. You have all those toys because you enjoy having and using them, not because they are actually making you any money; in fact, most of them are depreciating every day you own them. If you want to argue the Porsches are investments, treat them like it -- do the math above to see how much they really make you compared to other options, and buy/sell for profit, not because you like having them.***
Being straight up with yourself about how much of your money is consumption vs. investment is key, because that is the only way you can actually make good financial decisions. You make a lot of money and so can afford a lot of nice stuff. But you can't afford all the nice stuff -- and you certainly can't afford All The Stuff and retire in 10 years. You can spend each dollar only once, and the number of dollars you have coming in is finite (even if you do have a lot of zeros to the left of the decimal point). Therefore, if you want to be able to retire, you need to add that onto your priority list, decide where it goes on that list, and then be absolutely ruthless about cutting back on all the things that are lower priorities in order to free up $$ to fund that retirement. The really, really good news is you have a metric shit-ton of low-hanging fruit if you're actually spending $16-20K/mo.
And in the "don't bullshit yourself" category: stop saying you don't actually spend that much money. It probably does feel like that, because when you live in a super-high-COL area, you're surrounded by people who make super-high salaries and spend those salaries on super-nice things. But you need to realize that that's not normal. In reality, even putting mortgage aside, you are spending a metric shit-ton of money every month on stuff you don't actually need, just because that's what everyone around you does, so you don't even think about it. The key to getting ahead is to start thinking about it -- to make everything a conscious decision, in full awareness of the tradeoffs. You can absolutely keep your home and your lake house, if you're willing to work a lot longer and/or cut way back on everything else. You can absolutely keep your current monthly lifestyle, if you're willing to work a lot longer and/or get rid of some of the property and toys. Etc.
The really great news is that your salary gives you a whole world of options. The really tough news is that your salary gives you a whole world of temptations. The only way to weave your way through that is to have a plan, and then religiously track how well you're sticking to that plan -- track your expenses, note what is working/what isn't, adjust as needed, rinse/repeat.
*You argue that your car habit isn't any different than trading in and out of stocks "when you know what you're doing." The problem is that there are exponentially more people who think they know when to trade stocks than who actually do. The problem with trading is that you need to get the buy and the sell right, over and over and over and over again. And almost no one actually does that.
**My whole house burned last year -- freak electrical arc flash on new, modern wiring! Fun!
***BTW, I have a Porsche myself -- 2015 911 Carerra 4 GTS Cabriolet. I absolutely love it. So I am the very last person to shit on you for having a StupidCar, because my own personal StupidCar is some of the best StupidMoney I've ever spent, even on a dollar-per-smile basis. My objection is to deluding yourself that these are great investments. Maybe you can make money on them, maybe not. But you're buying them because you're a car guy and you want them, not because they're the best possible investment (after all, you haven't even done the math to determine how good of an investment they are, have you?). So calling them "investments," and telling yourself you make money from them, is just rationalizing buying another toy. You want a toy? Buy a toy. But own that -- don't bullshit yourself by calling it an "investment."