duntmatter I suspect if people here can help that more details will be required.
What is meant by "playback is completely gone"? Are both audio and video failing? In which apps?
Thirty minutes of app compilation after an update is atypical. How many apps are on the device?
Have either of the problematic updates involved the battery running out of power during the update?
Which GrapheneOS version (build number) is currently running on the device?