For .ca specifically: as long as you are a Canadian individual, or have a sufficient connection to Canada, or a Corp with a trademark registered in Canada then you are qualified to own that domain - but as to who is really checking I have no idea… CIRA complainants maybe?
Here’s some info about .world domains https://support.google.com/domains/answer/6300841?hl=en#zippy=%2Cterms-restrictions
Couldn’t help looking it up - so satisfied that it’s called a lounge of lizards