I tried to make a similar setup work in my Mi Pad 5 (it was my Home-Manager setup instead of VSCode only, but otherwise the same idea of Nix on Termux), however

I tried to make a similar setup work in my Mi Pad 5 (it was my Home-Manager setup instead of VSCode only, but otherwise the same idea of Nix on Termux), however it is really slow to evaluate Nix expressions inside PRoot. I would love to have a similar setup without all the ptrace overhead. Instead, I use a Chromebook tablet hybrid (Lenovo Chromebook Duet 3). Even with a much slower CPU (Snapdragon 7c Gen 2 vs Snapdragon 860), Nix is much faster thanks to ChromeOS' Crostini bringing a virtualized Linux distro. I would really like a more powerful Chromebook tablet hybrid with a more modern CPU and more performance cores (Snapdragon 7c Gen 2 has just 2 ARM Cortex-A76), but sadly it seems Google is not interested for some reason. I especially like this tablet because the battery life is so good (I can even get things done with <10% of battery because this still gives enough juice for 30 minutes of light usage).