Side goals before the teal mask commes out

After beating the game there are many side quest you can do like

-complete the pokedex

-compete in the academy ace tournament

-refight the gym leaders

If you beat all 3 side goals you can wait or play the gen 4 remake, arceus,gen8 dlc or gen 1 let's go

-only in gen 4 remake mine some stuff for money in the grand cave

-only in arceus catch alpha pokemon In every area

-only in gen 8 catch legendaries in the dynamax quest

-only in gen 1 let's go scavenge pokemon in the go park

-complete the pokedex in every game

If you did all you can wait until it commes out