Man, did I miss the memo where god themselves banned all manga authors from not ending the story post "getting together"? There's a lot more the story could have touched. More cosplay. College getting in the way. Gojo reaching new heights as a hina doll peep and so on! So many threads just left on the floor just cause they got together...
Then again, if it's because the mangaka is burned out or has health troubles, then it's more than understandable. One can destroy a story by making the author hate it and see it as a chain, and the other, well, that's self-explanatory, health always comes first.