How can I share my mac's internet connection while it's connected to a VPN?

Question

I have a mac running macOS 10.14.6 that's connected to Wi-Fi. I want to share its internet connection to some other systems connected to my mac's ethernet port via an ethernet switch.

If I turn on Internet Sharing and share from Wi-Fi to ethernet, it works fine. But my mac is also usually connected to a VPN (in this case using Viscosity, an OpenVPN client). So long as the VPN is connected, internet sharing stops working. The other systems connected via ethernet receive an IP address via DHCP, but no traffic can get out of the local network created by my mac. This is illustrated by traceroute that fails like so:

traceroute to 1.1.1.1 (1.1.1.1), 64 hops max, 52 byte packets
 1  192.168.2.1 (192.168.2.1)  0.353 ms  0.302 ms  0.290 ms
 2  192.168.2.1 (192.168.2.1)  0.293 ms !H  0.259 ms !H  0.262 ms !H

Is there any way to get internet sharing to work while the mac is connected to the VPN? Preferably the other systems connected to it wouldn't be going through the VPN too, but that's acceptable if there's no other good way to get it to work.