[microcolonel]

Well, you chose to install it, you can configure it not to do this. For the vast majority of people, myself included, NetworkManager should have control of DNS resolvers (at least, when I have WiFi on a system. I usually don't use NetworkManager on Ethernet-only systems, since there's systemd-networkd).

[gerdesj]

Absolutely. My laptop travels across a lot of networks, wifi and ethernet, with and without OpenVPN and Mobile IPSEC. I tether to my phone. I have some IPv6 networks to worry about. Firewalld is expected to do the right thing as well. I have loads of NM profiles, one of which has several RFC1918 addresses for covering most bases when starting out with routers and switches.