Start by asking yourself honestly if you need an Instagram replacement or if you really just need a substitute to replace the dopamine you get from a behavior - meaning basically, you probably just want a new infinite scroll for when you feel bored, restless or awkward and need a diversion.
If that's the case, look at some of the stumbleupon clones or maybe the wiktok kind of tik tok style wrapper for wikipedia type apps. But if you truly need Instagram specifically, the good news is that pixelfed is mostly there, hard part is that you now need to convince many to come use it for it to "feel" full and fun