If anyone already pointed this then this post is pointless, I’m posting because I couldn’t find an open post to reply.
Citra version: Canary Build - 68fce6e
Game: Pokemon Ultra Sun
It is a known bug that happens after you beat the League, game freezes when you enter the Hall of Fame.
One solution was to go through the whole process with only 3 pokemons.
I saw one guy going on Pokemon Sun with 3 pokemons and CPU JIT disabled and other one saying that going only going with 5 pokemons it would still work.
I was able to go with 5 pokemons and with CPU JIT disabled.
I think it would still work only with CPU JIT deactivated (I can’t test, game saved after the credits).
I don’t know if it only works with Pokemon Ultra Sun or for all versions (U-Sun/U-Moon Sun/Moon).
i did it with 6 pokemons i am not sure which one worked but i tried two things i turned off cpu jit but it didnt work then i turned it back on and then tried the hall of fame editor on pkhex then added my pokemon on the first hall of fame tab after that it worked then i tried to verify if it was the cpu jit reset or the save editing i reverted to a previous save and then tried but it worked so im confused on which one actually worked try both of these and im supre it’ll work for you i am a noob when it comes to pokemon games so i couldn’t defeat hau\kukui depending on the game with 3 pokemons hence i tried hope it helps just noticed im posting this 5 years later but some people might still have this problem like me