You know, we used to develop on computers with less than a Gig of RAM. A phone with 6/8/12 GB should be plenty enough to to do some development on. Or even less if you don't need to compile.

Seriously, you can run the windows version of GTA V on a phone. It runs pretty ok as well.

I have no troubles compiling most stuff on a phone with 3GB RAM. I even worked on Mesa on it once when I was too lazy to set up cross-compilation. I only struggled with OOMs on some Rust apps so far (and I haven't even had zram set up sensibly back when I tried them, so maybe these would work now).