These days, Instagram is like checking out your friends’ vacation photos, but every other photo is an advertisement, and half of your friends’ pics are full of product placement.
It used to be a good place for sharing photos with friends and family, then for keeping up with photos by photographers who do work you like, then keeping up with photos by people who became famous for being on Instagram (I never really got the appeal of “influencer” culture), and now for keeping up with advertisements. Every once in a while I check in and it feels like I see more ads than photos from people I’m following. And it desperately wants to keep my attention - all of it.
Even without worrying about Meta vacuuming up as much personal data as it can, it’s just not enjoyable anymore.
As for alternatives: I’m still happy with Flickr (which is all about the photos!). Pixelfed is similar to Instagram but without the surveillance advertising (and it’s part of the Fediverse). And sometimes I just post on my blog or on Mastodon.