Next, per your suggestion, I created a local FydeOS account and logged in. With the local account, I was able to activate the android subsystem (via popup), and install Open Gapps from the FydeOS Web Store and configure it. The system then rebooted. After the reboot, the Google Play Store icon automatically appeared on task bar.
So, I logged out of the local account, and I logged in with my Google account and I was able to install various android apps from the Google Play Store. However, when logged in to my Google account, the FydeOS Web Store still won’t install anything (same “Unsupported OS” message).
I guess I’m good to go now, but that is a confusing workaround. Thank you for your help. - Mike P