One thing that was holding me back from trying Niri is its configuration was limited to 1 file with no way to override or include additional configs which is quite important IMO for having 1 main config that you slightly change on different devices if you want to make your dotfiles public. For example you can have gitignored "local" files on each device to handle overrides.
Just the other day the author merged 2 PRs to handle both use cases https://github.com/YaLTeR/niri/pull/2482.
It's not in a release yet but hopefully soon.
Yes, this feature had been in the works for quite a bit since it required non-trivial changes to do it "the right way". Very excited to see these changes merged finally!