I have been seeing it from the first invites came out. It has gone from “nothing to do see there” to “maybe something rarely” to suddenly, in the last few post-Trump weeks, “a lot of something — and most of them is pure spam (of course for me; I am sure it’s beloved content for others). But of course there is no way to filter that out without losing on other things or being to square one “almost nothing to look at”.
Besides, as we have seen with Signal and Mastodon — people will just go back to what they are used to and where most of the crowd and noise is.