Most people store their dot files (including their vim config) in a git repo and just check out a copy on any machine they use. That's what I do (git+stow). I can be up and running on a new system in just a few seconds.
Does anybody know a saner way of doing this cross-platform? I've resorted to doing platform checks in my .bashrc and don't get me started on the OSX / Linux differences in .platform, .bash_platform, and .bashrc sourcing.
And when I tried termux on Android, oh dear lord. The whole thing breaks because of permissions issues. Had that issue on WSL too.
Lowest-common-denominator for linux and mac, mostly just "make it work if you notice it's broken". I have one file that's bash magic, and link it to everywhere it might be needed - bashrc, bash profile, etc. It's kind of monolithic, not great but at least 100% consistent for what ends up where, and avoids sourcing external stuff or requiring N different files to work. You'll see some of your pain in the repo history, change X to Y to make it osx or *nix compatible based on whichever is my primary platform.
Same goes for vim, just absolute basics for vimrc and a few very portable plugins and niceties hardwired. No package manager, just a bare directory.
And when I tried termux on Android, oh dear lord. The whole thing breaks because of permissions issues. Had that issue on WSL too.