Personally, I find basically everything about Instagram bad. The only reason I use it is because a lot of my friends share their pictures there.
Their app is full of bugs, at least on my regular Android phone, dark mode always messes up, ghost notifications, random crashes, etc.
The platform is full of bots. My profile is set to private, so everybody who wants to follow me needs to request first. On some days, I get requests from 10+ profiles trying to sell porn. And that's without following any big influencers, just friends.
The bots also invade basically every public comment section, trying to sell porn or NSFW snapchat. I don't get why they are successful, but I assume they are, given the scale they operate.
Their TikTok clone feature that basically completely spams my discover/search tab is full of content taken from TikTok or barely dressed girls trying to push their OnlyFans. Maybe that was the plan, I find it just annoying.
And now to their ads, easily one of the most annoying parts. Given how much data Facebook/Instagram is collecting, you'd assume they'd somehow manage to show interesting and relevant advertisings. At least for me and some friends I talked to, that is absolutely not the case. While it feels like every third post is an ad, there is nothing relevant at all. Basically all ads I get on instagram are trying to sell me 100k passive income online courses, cheap Chinese drop shipping products, knockoff products or trading apps (something I was never remotely interested in either).