This should have been the headline.

If you’re being fediverse-specific you could set up your own instance, federate with everything, and have it save only the content you’ve interacted with. It’s a pretty narrow archive so it wouldn’t be too resource intensive. And if you’re techy it wouldn’t be too hard* to write a native activitypub client that did only this if you were active on eg lemmy and mastodon and pixelfed

• for certain definitions of “too hard”