I won’t claim to be a guru, but I can provide some explanation of the process from my slightly rusty memories.
Metalink will provide a list of mirrors that should be close to you and can provide the repository you’ve requested (with the right version and architecture).
I believe it will also only return mirrors that are sufficiently up to date - if you look at Propagation - MirrorManager you can see a visualisation of the mirrors catching up as they download the new content from other mirrors. I think that graph is from mirror manager checking the mirrors explicitly, but mirrors also report back in to mirror manager when they update themselves.
If you never see mirrors from your country, then it’s possible that a) there aren’t any, b) they don’t carry the specific content you want (although for x86_64 and supported versions that’s less likely), c) aren’t up to date, or d) metalink thinks that the other options are better, even if geographically they might be further away.
Also thanks to Kevin Fenzi for his explanation here - Fedora 40 mirrors : errors leading from Western Europe to mirrors based in UA & RU? - #24 by kevin - that provides some more detail, although the rest of that thread is on a slightly different topic.