I think that's a cop-out. There are no objective measures of these things, the meaning of "how long you linger" or where you move your mouse are completely made-up by the coders who wrote the algorithm. They don't have to be a signal of anything, but the companies just go ahead and decide it means something. Then Goodhart's Law finishes the job.
Part of what makes these social networks echo chambers are the unconscious ways we navigate them: how long we linger on a post, stay in the site, etc. I’m not sure whether conscious decisions like being judicious with the follow and block buttons would pull you into more of an echo chamber than the algorithm does, especially if you’re selecting for things other than “this captures my short-term attention span.”