This is limitations of scylladb and their api service requirements.

They haves something called a service agreement. That means the API is required to respond in 99% 99.999% etc. and by limiting to 8mb for files, charging for a bit more etc. they can both monetize and enforce guaranteed api requirements internally.

Legitimately most of them

Bluesky probably will be the winner; but it may be an activity pub site

He fired the worlds biggest experts on the technology at Twitter and thought he could do it better with a skeleton staff. Now the dead body rots. The skeleton is there. It smells musky, and the site has died.