Regarding crypto I'm not sure what are the laws but I can tell you what's happening now.
A few years ago there were
no withholding taxes for crypto and it was easy to register at local
crypto exchanges without any formal ties to country (except a local
bank account which would be used for deposit / withdraw).
In 2023 some foreigners got their crypto exchange accounts closed / frozen / reKYC requested / reKYC requested but no options for foreign docs. There were some regulatory changes and apparently many exchanges were not sure what are the requirements for foreigners. It was confusing.
I got a scary-looking message popping up all the time "All deposits stopped, resend your docs" with a link to a crypto exchange page saying that I'm fully verified.
Just a couple months ago verification became available again. bitkub.com which I use asks for more docs than before, but it's mostly to effect of "more ties to Thailand than a tourist". A letter from university would suffice for a student, or a driving license which is easy to get. No formal requirement to have a work permit / be a tax resident / provide Thai TIN.
Still no withholding from crypto exchanges. Work fine. Not exactly sure if they are going to slap me with a 15% bill on turnover by the end of year. Well, things are mostly not crispy clear here but tend to work out well, one just needs to get used to that...