While my group & I did get a few events we wanted, we got none of our higher priority ones. It happens (as most of the other posts above shared as well).
What I would encourage would be to try a few events from the ones left. My first Gen Con (many years back), I wasn't able to get any (ANY!) of the events I wanted, so I went with "Plan B." For example, I didn't get any of the D&D events I wanted, so I signed up and played a Conan RPG. It scratched the D&D RPG itch, and I met some really nice people. I still (fondly)remember the event almost 2 decades later. Another time I signed up for some zombie board game (not Zombicide). Again, had a fun time with some great gamers. Gen Con is a great place to try out new-to-you and obscure games.
I would also suggest to perhaps run an event of the game you're looking for. Sure, it's easier to play than run a game, but at least you're playing what you want to play. Gen Con, after all, needs GM's too. One year I ran 8-9 slots of D&D games. That was way too much, but it was an experience. You don't have to do that; Just run 1 event. You pick the day and time. You'd be surprised how fun and rewarding that can be.
None of this is intended to be antagonistic. I'm just trying to offer alternatives and suggestions to still have a fun time. While I don't know you (OP), I hope you find a few events you & your group like and that you have a great time at Gen Con, even if you didn't get the events you first wanted. Cheers,