Apollo still works perfectly if you sideload it: https://old.reddit.com/r/apolloapp/comments/14nzii3/how_to_c...
https://github.com/ichitaso/ApolloPatcher/releases/latest
https://github.com/EthanArbuckle/Apollo-CustomApiCredentials
https://github.com/ichitaso/ApolloPatcher/releases/latest
https://github.com/EthanArbuckle/Apollo-CustomApiCredentials
Edit: oh never mind, I've been digging into the links but it looks like it's iOS - only. So that explains why I've never come across it before.
In my experience, based on reading complaints about the app, is that many use it for 5 minutes on the default settings and claim it is the worst app ever made.