That is the logical explanation, for sure. But given what we've seen from Sidious I think everything was intentional. You can assume that if you think anything in Rise of Skywalker was possible that he was playing 4D chess from the beginning of the Saga if he can get Death Star Destroyer fleets built in a few years and clone and put Snoke in place, etc. that he has to have forethought and that he chose to deform himself for 2 reasons.
1. Sympathy from Anakin, he knew Anakin "needed" him to save Padme, and the frailer and weaker he looked the better. It would be.
2. Sympathy from the Republic and reason for his reclusiveness and high level of protections. He knew that by looking deformed that he could skirt being in the public eye when he ran the empire.