Is there any immutable distro that's based on Hyprland? I really like their approach to tiling, but at the same time I prefer to have a solid experience without worrying that the next update might break some dependencies.
No distro is really based on a window manager or desktop environment. Some provide defaults and premade configs. I kind of doubt any include hyprland as an option at installation, but, Wayland compatibility notwithstanding, there's nothing stopping you from throwing hyprland on whatever you would like. The best approach is to take a Wayland-ready setup, like Leaflet suggests, and just install hyprland.
Yes, I was thinking about that as well and even found some guide on how this can be done. Actually I was eyeing uBlue but it should be exactly the same procedure for both.
I've been using wayblue on my own desktop. They have sane defaults & very pleasant theme. They do a good job keeping their image up to date & enable auto-updating from the get-go.
You could try Guix (either standalone or Guix system). You can have a immutable profile, an immutable home environment with centralized configuration and much more!
The ability of having immutable environment and dotfile configurations is amazing.