Should I meet my boss when I travel to his/her country?
Etiquette says nothing about that (only when on business trip), but there are rules based on basic politness. You should not "invite" yourself, you should not bother, you should/could just inform.
It happened to me, with colleagues (N-1 or N+1), but never with my boss. Anyway, I was always informing them in a informal way: "oh, by the way, I'll be in [country] from [date to date]. What can/should I do/visit/not miss? (or is there something I can do while visiting?" Why wouldn't you just do that during a meeting/zoom? With your own words or variation.
I'd recommend just givin informal information about the travel and disponibility, and let them decide. If they invite you, set up the meeting together, if they just wish you a good trip, thanks and move on... They may not invite you, because they want to give you a real break, that's also respect.