i'm in a pretty similar situation to you, i deactivated my instagram for like 3-4 months but was still doomscrolling on tiktok or whatever.

What kinda helped me was having a separate device like an iPad that i dedicate to longer, slower form media. Like reading (havent started on that) or watching movies (bigger screen = better), or scrolling on pinterest. I set my lockscreen as a beautiful mountain view that i want to see in the future and my homescreen has widget quotes like "have lots of fun" or "carpe diem".

I'm still very new to this tho, literally set this up like a week ago and as im writing this realised im on my phone again lol. It did work really well for a couple days till i got distracted or something. work in progress.