Indeed. Some companies limit to countries, some to timezones (+/- a few hours), some to regions like you mentioned, and others might have a language requirement. I've been trying to figure out how to surface that properly without making it too complicating for either the poster or the viewer, and I'm honestly not sure yet.

Though timezone is generally a proxy for the former. I don't think many US companies asking for UTC-(7-5) for example will entertain European applicants willing or happy (I know it would suit me better!) to work those hours.

Maybe don't show anything unless a specific country (usually US) is mentioned? Can add a flag emoji for those.

Timezones are often more flexible, and I wouldn't bother too much with that. But location often doesn't have that due to legal hassle etc (other than visa sponsorships).