I have YTTV, Netflix, Disney+ etc working successfully. Initially none of them were working while rooted. It takes some fairly big changes, but I thought I'd share.
Essentially, widevine needs to be set to L3 (lower quality as it's not protected). There is a module called liboemcryptodisabler that typically accomplishes this but it doesn't work for our device. Oneplus moved the library (liboemcrypto.so) to the "odm" partition which both the module and Magisk don't support. There is a fork of Magisk called Magisk Delta (by HuskyDG) that allows magic mounting of extra partitions, including "odm". I made some tiny and "hacky" changes to the module and now widevine shows as L3 and video apps work for me.
Use at your own risk, I'm not responsible for any damage, etc, etc.
- Magisk Delta - Required. I'm currently using delta-5. Zygisk and MagiskHide enabled and DenyList configured.
- Universal Safety Net Fix - Module. Needed to download the media apps from Play Store (and maybe other reasons). I'm currently using v2.4
- liboemcryptodisablerodm - My custom module attached here. Based on the original liboemcryptodisabler by ianmacd.