My question then is, which are the best countries that can access these sites without issues, and pass all KYC checks? I'd love to hear your opinions!
KYC is the simplest issue of which service platform to use. If you can't access it, there's no need to force yourself to use it. Although as far as I know, there are also services that support verification of these types of accounts, but it is always unsafe and unpredictable incidents can occur.
I think it's just a matter of legality in this area, which the OP can reach. And actually, I can feel that the countries that accept gambling all have developed economies. As for me, I will choose to move to live in Asian countries, and I quite like casinos in Macau. But anyway, I don't choose such a life, for gambling experiences, I only stop at entertainment.