I have notice that some emails seam to be blacklisted or even blocked.

I can not receive any emails from them. And that  seams to be consistent issue. My guess that is due to region blocking I am form Lithuania (Eastern Europe) and the emails in question were too.

Strange thing is that some other emails form region works and the ones that don't are not even listed under spam just never received.

I realize that changing region blocking policies is probably not happening so this is also a question to people who have analyzed alternatives. Basically what would yo recommend Microsoft 365 or Gmail Apps for Business?