Any of the ones you mentioned would probably work good with nix too. I don’t really care about the config being scriptable at all, it was just the first terminal that easily let me set all of the keyboard shortcuts I wanted, so I stuck with it.
I suppose I'm a bit of an extremist, though.
I put config in dir, launch app. App should look like config.
If it doesn't it's the app's fault.
There are a limited number of applications I tolerate this behaviour from, but not many.
But it's always better when the application itself is cross platform and uses just a single config file.
(Just setting all of the knobs on macOS is a massive hassle and only part of them can be automated in a deterministic way...)
For more and more of the cross-platform headaches, I've actually found myself treating the OS as more of a virtual host, and spending the plurality of my time configuring layers that run in it (modify .zshrc where it can do the work of iterm/wezterm, if it can be done in .emacs then do it there).
I get the feeling that I'm not far off shipping personal nix containers around, but there's still a little too much friction between having containers work and working on the OS itself.
I've been using it for years and didn't touch the templating until this spring actually, I just had if statements in my setup bash scripts =P