Basically I use git for .local/dotfiles/ which are then symlinked to the relevant files like .zshrc or .emacs.d/init.el. Then I just keep that repo up to date with git pulls. Works across 2 macbooks, a Fedora workstation, and a Fedora headless server.

Couple of bits from a guide I wrote recently: https://gist.github.com/aclarknexient/0ffcb98aa262c585c49d4b...

    # store stuff here that you don't want in github
    [[ -f $HOME/.zshenv-local ]] && source $HOME/.zshenv-local

    # depends on 'brew install grep'
    [[ $OSTYPE =~ ^darwin.* ]] && alias grep='ggrep --colour=auto --exclude-dir={.bzr,CVS,.git,.hg,.svn,.idea,.tox}'

That OSTYPE is great for all those little bits that are unique to each operating system. The zshenv-local is in .gitignore, so you can keep tokens, api keys, etc etc in there. OSTYPE could even be used to import specific files like .zshenv-darwin or .zshenv-linux-gnu

If you're ssh'ing between your hosts, you can use something like this:

    if [[ -n $SSH_CONNECTION ]]; then
      ZSH_THEME="afowler"
    else
      ZSH_THEME="powerlevel10k/powerlevel10k"
    fi

It's not fancy and doesn't use cool tools, but my setup works for me just fine.