The TikTok algorithm is generally seen, by its users, as being really good. Once you've spent some time there and your For You Page really gets going, it really feels like it's For You. And the algorithm there doesn't seem to penalize people doing original reporting, current events explainers, science content and educational content, musical performances, tutorials, etc., alongside typical social media stuff like viral challenges and pet videos or whatever. The general "vibe" is that TikTok feels more "authentic," while Reels is mostly manufactured content (dance videos, AI slop, "funny" compilations, lots and lots of ads) and YouTube Shorts is where comedy skits and reuploads of TikTok content go to die.
Away from genuinely interesting, personalized recommendations, to be replaced with depressing rage-bait algorithm of sites like Twitter.
I made the switch to YouTube shorts when tiktok went down and my experience is largely the same, if anything I'm seeing more educational material on electronics and programming which I enjoy. No ragebait yet unlike TikTok. No idea about instagram reels though.
Meta's algorithm on IG has gone so far down the toilet over the years. Before I deleted my account last year, I'd have to scroll through 5-7 sponsored posts before I'd actually see something from someone I actually follow. Nevermind the amount of regular old ads that were inserted into my feed.