Quick info, the link does not work.
You need to put it in the address part aswell (like this [https://github.com/madmaxms/iconpack-obsidian](https://github.com/madmaxms/iconpack-obsidian)
Here is a working one https://github.com/madmaxms/iconpack-obsidian
You can even have all nixpkgs on a different distro through the nix package manager
That is very cool. Thanks for sharing. If you need some additional repos (like OP), you can probably add them through some commands in the “pre_init_hooks” option.
It should be possible. Although probably very complicated. Have a look at https://distrobox.it/. It allows you to tightly integrate containers into your desktop, including accelerated graphics, some devices, your homedir, etc. It can even automatically install desktop shortcuts. (You can disable the integrations of course) Even tho it uses Podman instead of docker, AFAIK it should be 1:1 compatible with docker for your usecase.
If you’re content with a web-based JS-App, try https://paint.js.org/
There also are distros with some kind of similar safety net. Immutable distros usually let you Boot previous versions if an update breaks something. This usually means that they need a lot of storage tho. https://itsfoss.com/immutable-linux-distros/