Unfortunately those are not platforms meant for archiving, it’s in their own TOS they can take down any content or entire accounts at their own will and for undisclosed reasons. Also those platforms are subject to shitty practices like report abusing, yet another reason to put your content in danger.

Also unfortunately they are very attractive because of the influence a person can build with large network of followers in those platforms and how they can leverage that.

I don’t see a plausible solution or alternative. Instagram, Facebook, are the platform of the masses and where your content has the highest exposure. People today aren’t browsing “the web” like we used to back then. Instagram/Facebook are the internet.