I'm kind of in the same situation, I recognise that especially social media are really bad for my mental health, and being a highly sensitive person, my brain cannot sustain that kind of constant bombardment of visual stimuli. I believe being cronically online is a way of maybe find a distraction from my emotions. So here's what I'm trying to do: I just try to be as creative as I can be. Whether it's sketching with a pencil, discovering new music, gardening (even buying a little plant that doesen't need extreme maintainance can do!), and lastly I very much reccomend trying penpaling. You can search for a penpal, start to build a connection and then when you both feel like it, exchange adresses and start sending letters to eachother. You can write how you are feeling, create little surprises, go out to search for magnets or postcards or stickers! It's really nice because once you concentrate on putting together a letter and therefore you are putting the effort to deliver to a friend something great, they will do the same. It makes me feel really good and seen and cared for, and I'm able to do the same and occupy my time for something nice. :)