What good is integrity if nobody uses Firefox ? That was the main reason they added EME support in the first place. Firefox staying relevant in the browser market is a better strategy in the long run than a hard line stance against DRM.
Maybe go even further outside the box, use gngr: https://gngr.info/
This was rather the point of Fall of Men ("Zeitpunkt des Sündenfalls") in Firefox' history to me. It was also the point in time where I stopped donating to them.
Make the zero-tolerance for DRM a unique selling point of Firefox.
You just have to reframe it to something like: "protects you against websites that try to plant DRM-malware on your computer".
In summary, if you already have Firefox, you don't need to go download a separate build to opt out of DRM. You can just uncheck the "Play DRM-controlled content" checkbox in the prefs to get to the same configuration.