My comment to people in similar situations, is to always remember that if you have that much savings, you are closer to retirement than you realize. If you can live off of a 4% drawdown, then you have very little risk long term of ever touching your principle in a very conservative index fund investment (stock markets historically in the US average 4% above inflation, and I suspect that's true globally). I'm not sure what the russian equivalent to Vanguard is, but I'd he surprised if you didn't have access to similar low cost investment.

Sometimes all it takes is another couple years of slogging away at a job you hate to get you to a critical mass where investment income matches your yearly expenses. At that point all risk of quiting is basically gone, and you can pursue whatever you want.

Also keep in mind that seven years is a pretty common number in business for a good product to become successful. You can have 100% growth year over year for 5 years and still only have 32 customers. So it may make sense to hold off until you have slightly more runway than 5-6 years savings.

But doing the math, and putting dates on calendars can do wonders for how you feel about going into work.

Also, you sound like you're in a really good spot no matter what you decide. Good luck!