Eet de rijken!

AFAIK, you do need to change your email on all your accounts individually. However, you don’t need to change all of them immediately. You can (and should) change over the most important accounts you have, and then you can set up a forward on your gmail adress, which then catches any less important accounts and forwards them to proton, and update those accounts once you remember they exist.

Here’s an idea: Maybe don’t put people in solitary confinement in the first place?