Internet connection and DNS routing are broken from WSL2 instances, when some VPNs are active.
The root cause seems to be that WSL2 and the VPN use the same IP address block, and the VPN routing clobbers WSL2's network routing.
This problem is tracked in multiple microsoft/WSL issues including, but not limited to:
WSL2 uses a random network from the 172.16.0.0/12 RFC1918 private IP address block. And our VPN uses that address block, too, with a route metric of 1 (= most preferred.)
This breaks networking for WSL2. Meh!
While messing around with the interface/route metric of the VPN network may work around the problem, it also reduces the priority of the VPN. We do not really want this. Additionally, changing the interface metric does not seem to be permanent, so it requires more work when it breaks again.