If you want to override that permanently then follow this post: Updating the system and git push is slow - #9 by Usr1
I personally don’t like any solution involving manual changes to resolv.conf because you don’t get the correct dynamic behaviour. The way it is supposed to work is that when you dock, it will use the DNS servers dynamically associated with that interface, and when you undock, it won’t. When you switch on WiFi, it will go with that. When you switch on cellular, it will go with that. Whatever is on and connected gives you DNS servers and the set of valid DNS servers is maintained dynamically, automatically, behind the scenes.
So you have to
a) use DHCP, and
b) allow resolv.conf to change dynamically, in effect, as interfaces appear and disappear.
This was the whole reason that resolv.conf changed from its original, completely static, config file to something that is in effect dynamic.
For example, on my desktop, which admittedly doesn’t really need dynamic behaviour (unlike a laptop or a phone, both portable devices) … resolv.conf says only and permanently nameserver 127.0.0.53 and systemd-resolved listens on that IP address for DNS requests and it worries about interfaces appearing and disappearing so it knows where to relay DNS requests to.
I don’t know why that isn’t working for you.
Not a serious error. That relates to using DNS for service discovery. Since DNS isn’t really working properly at the moment for you, you won’t be using it for service discovery anyway (and even if DNS were working, I doubt that you need to use it for service discovery).
Unrelated to DNS. It may or may not be a bug. It may be intentional behaviour. Or not. Probably best to search the forum for discussion on that.