I enjoy Twitter, now called X. It's not what it was before Musk took over, but to a considerable extent the experience you have depends on who you follow. It's interesting, good for politics, and there're tons of nice animal photos and videos. I've never used Facebook. YouTube is good for music. Snapchat is good, I suppose, if you want to make sure your messages will disappear quickly. And you forgot Instagram, which you need if you want to be an Influencer. Oh, and there's Slack. I don't even know what it does; it seems mostly to be a work thing.
But nowadays, what's really important are podcasts. I suppose part of the reason for their popularity is that a great many people commute to and from work, and they want something to listen to, but not look at. Yeah, there's also Sirius XM, which has longer format shows. Most podcasts seem to be relatively brief; maybe 15 to 20 minutes. But I haven't listened to many. And of course there're audiobooks, but I hate being read to.
The TikTok videos aren't really blurred at the sides. It's just that most people there use Portrait rather than Landscape mode when making their videos.