I've experienced something similar, with LinkedIn often edging out Twitter and Mastodon—though Bluesky fares a little better for my content, in terms of getting good conversations started on most platforms.
The annoying thing is, Bluesky and Twitter especially don't seem to be conducive to good conversational replies (especially since they get so disjointed). Mastodon is a little better there sometimes, but so few people (comparatively) are on that platform a lot of conversations languish.
Blogs with comments and forums are still the best for actually thoughtful conversation, with back and forth... but so many communities break off into Discord nowadays, it's hard to have anything as centralized for conversation/thoughts.