Yeah, it sucks. But I think that at a certain point it will need to happen if we want to make ActivityPub better with better portability.

I think there's a FEP that could (or fixes) this. To my understanding ID can be any URI, so there are better ways. I guess it's hard because it would brake a lot of stuff or how mastodon is build.

For a second I thought the ActivityPub specification got updated.

Literally one of the reason for the existence of this thread.

I recently wanted to do the same and came upon ShareX, it did a pretty good job.

GitHub F-Droid