Last time we bought, we looked at how much we were spending each month on rent. Let's just say $2000 for the sake of easy math.
Then we looked at how much we were saving and investing at the end of each month. This is different from your "we have low spending assessment", because it is what you *actually* have left over each month (on average), not what you get if you write down what you think you spend. (If you obsessively track spending, they will be the same. But if you just sit down and write down all the things you can think of, you are almost certainly well short of actual spending. One-off expenses, annual things like car registration, gift spending, impulse buys, upgrades, etc. all add up.
In your case with what you provided, this disconnect in actual spending vs. "what I wrote down when I had to think of things I spend money on" is significant, which is all the more reason to simply use what is leftover on average over the recent 18-24 months. (and then accounting for income increases, major expenses you paid, major expenses you didn't have during that time but will eventually like a car, changes in lifestyle up or down, etc.)
So, if over the course of the past 2 years (and accounting for any income or spending increases in that time that make the older data less accurate) we averaged $1500 in savings in addition to our automatic investments which we won't touch, then we could technically afford $3500 in house expenses (mortgage, insurance, HOA, maintenance including escrowing for future large issues, taxes, etc.) That's our current $2000 home expense of rent, plus all of the rest of our monthly unspent money. When we did this, we decided we weren't comfortable cutting it anywhere near that close, but it less us see what things would look like. So if we decided we wanted to keep at least $600 of that savings/cushion, then we knew we could spend $2900. Figuring what that looked like as a purchase price was pretty easy once we had that numbers (and could estimate taxes, insurance, etc.)
To me, that's the way to do it unless you have a very, very clear picture of your spending. It tells you what your current lifestyle and spending allows you to spend on a house and leave everything else except supplemental savings untouched.