My concern is about minimizing your downside risk. You are very highly focused on the tech industry -- your job, your investments (other than the cash), and your real estate (both values and rental rates) are all reliant on the tech sector. Which mean that a single economic shock to that sector fucks you over three different ways. The dirty little secret no one really talks about is that the kinds of economic downturns that cause drops in the market also lead to major layoffs, which in turn seriously affect housing values, as people can't afford those home prices without those high-paying jobs. AMHIK.
That kind of concentration may make sense when you're in the growth phase, because if you happen to pick the booming sector at the start, everywhere you put your money will ride the wave with you. Even there, I wouldn't recommend having your investments so aligned with your job, though, because if your investments crash, you need your job to help you build them back up, and if you lose the job, you need your investments to carry you. But if you want to be super-aggressive and put all your eggs into the tech basket, then that will definitely supercharge your returns as long as the tech sector stays hot.
The problem is that there is no sector out there that stays hot forever. Over a 30-50-yr retirement, the tech sector will crash (it's a "when," not an "if"). You can handle that right now because you have a job. But once you FIRE, you lose the safety net -- there's no steady paycheck to tide you over until your investments/rentals start to make money again. If you don't have something else to fall back on, you end up selling those assets at fire-sale prices just to cover expenses, which is the quickest route to derailing all of your plans. So when you don't have that safety net any more, you simply cannot afford to have all of those assets tied up in a single sector; you need things spread around, so that when one area is dropping, another is still providing you the cash flow you need.
So, no, I wouldn't advise more RE -- particularly since that's a reasonable investment only if things go really really well (if your profit comes only from appreciation, then even a "meh" market isn't going to meet your needs, and you'll have massive $$ held up in illiquid assets not generating any kind of return at all). The only way I would advise more RE is if that particular property pencils out immediately -- i.e., that the rental income itself is giving you a reasonable return from day 1. There are a bunch of people who do very, very well with real estate investing as a path to FIRE -- but they're also very picky about making sure the properties they buy are profitable immediately, not just hoping that values will rise over time. If you are in an area where that just isn't possible, then you should instead focus on putting your cash in some other investment that is not so closely tied to your industry/location.
What that other asset should be depends on your FIRE timeline and other income sources. Given the aggressiveness of your stock portfolio, you may want to balance that out with a good chunk in CDs or individual bonds -- enough to cover your income needs for 2-3 years, say, to give you time to ride out any short-term market blips. Or if you want to be a more active investor, you can research industry sectors that tend to be hot when yours is cold, and cold when yours is hot, to at least give you a chance that part of your portfolio will be in decent shape. Of course, in a major downturn, everything tends to go down together, which is why I am a big believer in keeping a good-sized chunk in CDs in any event.
