This was my thought as the comments do not add up.
This should only be effective for openresolve
This is for systemd-resolved
And if using systemd-resolved this should be a symlink with a header like
# This is /run/systemd/resolve/resolv.conf managed by man:systemd-resolved(8).
# Do not edit.
#
# This file might be symlinked as /etc/resolv.conf. If you're looking at
# /etc/resolv.conf and seeing this text, you have followed the symlink.
#
# This is a dynamic resolv.conf file for connecting local clients directly to
# all known uplink DNS servers. This file lists all configured search domains.
#
# 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.
#
# See man:systemd-resolved.service(8) for details about the supported modes of
# operation for /etc/resolv.conf.
But you are obviously starting systemd-resolved.
This will be somewhat helpful … though we have already established your configs are broken.
PS.
This is definitely not used by default - NetworkManager is - was this also consciously replaced?
PPS.
If you dont want to wait on exchanges here … there is an old post outlining setting up systemd-resolved here: