Tailscale in NixOS with networkmanager

I’m using nixos with networkmanager, and since activating tailscale’s magic DNS, I can see that it replaced nixos’s auto generated DNS with its own:

# Generated by resolvconf
search matrixai.org.github.beta.tailscale.net
nameserver 100.100.100.100
options edns0

This is actual /etc/resolve.conf.bak is my original DNS:

# Generated by resolvconf
options edns0
nameserver 1.1.1.1
nameserver 1.0.0.1
nameserver 8.8.8.8
nameserver 8.8.4.4
nameserver 2606:4700:4700::1111
nameserver 2606:4700:4700::1001
nameserver 2001:4860:4860::8888
nameserver 127.0.0.1

Is there a way I can get back my original DNS list? Is there a way to make tailscale not override my own DNS, I’m using the tailscale service, and I’m using the insertNameservers option.

networking = {
      networkmanager = {
        enable = true;
        dns = "dnsmasq";
        insertNameservers = import ./nameservers.nix;
      };
};

How would tailscale’s DNS service work with my existing nameservers?

For now I have to disable the DNS, since this silent override of my NixOS’s configuration of DNS is surprising. Especially since I was expecting that tailscale wouldn’t override my local DNS settings on Linux (the option on the GUI wasn’t even enabled!)

I can specify these DNS settings by hand. How do I tell tailscale to not override my /etc/resolv.conf?