In my opinion, the best keyboards are the ones that are very easy to clean :) Ideally, switches should be chosen based on your hands since everyone has different preferences. I'm currently using Keychron K5 SE ultra-slim with Low Profile Optical hot-swappable "Banana" switches, and it's the most comfortable keyboard I've ever had — and it's not even that expensive (for a mechanical keyboard). Before that, I had SteelSeries' top model, and it broke after about a year.
Building custom keyboards is next-level, and I think I'll pass on that. What matters most is that it's comfortable to type on and easy to clean. A piece of advice for beginners: don't buy keyboards from Logitech or Apple. They're overrated and not worth their price.