From my /etc/resolv.conf on Debian trixie, which isn’t using openresolv:
# Third party programs should typically not access this file directly, but only
# through the symlink at /etc/resolv.conf. To manage man:resolv.conf(5) in a
# different way, replace this symlink by a static file or a different symlink.
I mean, if you want to just write a static resolv.conf, I don’t think that you normally need to have it flagged immutable. You just put the text file you want in place of the symlink.







If I’m understanding you aright — you want things to monitor your system as well as a system tray to let other software stick icons in — I think that the norm, dating back to X11, is to have an applet for the dock/wharf/bar/whatever-you-call-it that provides a system tray.
I’m currently using waybar in sway, and it has a system tray function and supports hyprland. The only programs I can think of off the top of my head that I’ve used that have applets that don’t are conky and GKrellM.