Not 100% sure if this isn't due to something missing but there appears to be
other recent complaints on the internet.
Possibly related to https://bugzilla.mozilla.org/show_bug.cgi?id=1732955

I've updated from Tumbleweed's 92.0 to mozilla:Factory's 92.0.1 and installed
the only widevine package I can find chromium-plugin-widevinecdm, the 
"Widevine Content Decryption Module provided by Google Inc" is enabled.

My laptop's hard drive recently died and I had to reinstall from scratch and I
usually use the Netflix Windows 10 app because I can download and watch later,
this is most probably the first time I've attempted to watch netflix on this
new Tumbleweed installation.
I'm going to boot to windows 10 and try that Firefox in case I can find some
useful information