Custom Domain accessibility question

I have in the past tried to setup two different emails on personal domains: a .xyz and a .net domain. In both cases I have come across multiple online services that refuse to accept them as valid email addresses for sign up or to change my address. My question is: Do I NEED to buy a .com domain or can anyone confirm other domains that do not seem to be filtered this way such as .IO or similar?

Online services often do a terrible job with keeping up with TLD’s. Keep in mind, this channel has a *.tv TLD, which at one point also was problematic for me. You could consider buying a .com domain to set up an alias to your main e-mail, so you only have one inbox to maintain.

I currently use Proton mail after migrating most of my accounts off gmail but I want a portable email address so if I ever move providers again I can just setup my custom domain at the new provider and not have to change addresses. So if I get a .com domain ill just use it as the main/primary address. I just wasnt sure if my addresses were being filtered because of the tld I was using or because the address diddnt belong to an established business name or major provider. My question was to see if any of the community here had setup a custom domain address without running into this problem, and if so, what tld they were using.