Well most people say around 1k (euros) might be enough and somehow I agree, but there are also other factors to take into consideration. First of all, winnings in poker are never guaranteed, so there's no way u can rely on that (unless you already have 5-6 digit sums in your poker winnings, and even then I don't recommend it), but the real question here is: why would u want to quit your job? If you don't like it, try to make a change in your professional life and find something that u are enthusiast about. Poker can be great, but it's not everything in life (neither professional, nor personal) and shouldn't be. I know it's hard if u invested many years, maybe even decades in your career, but change and potential fulfilment beat regret from miles away. In my opinion I think it's wiser to choose the change
Maybe u can quit your job when u are close to retirement, but being old(er) comes with all sorts of problems....
All the best and good luck.