As far as I know, I can only favorite emotes while in an online match. This means I always have to rush instead of taking my time browsing since I’m keeping someone else waiting

I agree it should be easier/more intuitive but you can actually do this by making a private lobby while toggling the “listen-server” button.
This puts you in a private match hosted on your own pc giving you as much time as you want to curate your favorite emotes without worrying about other players.
Ay appreciate it, I was hoping someone would tell me a workaround to it if I made this post lol