The OLED is designed around suspend/resume for gameplay. I think the suspend/resume snapshot is continually updating but can't cope with duplicate frames and audio if there are too many duplicates, which is bad for anything that repeats, and weapon fire repeats a lot.
I have no idea what would fix this, but you need X4 to minimise lockups based on duplicate video and audio to cope with the Deck. Even if this is not the cause, having handlers for duplicate video and sound instructions would give a more stable experience for everyone else. In all probability you have such handlers already, but they need to keep up with the lower requirements of the Deck.
I've tried all the optimisations on my end I can get at, and have reached the point where fiddling with the Deck's settings won't get me any further. If you do a tearing catchup every thirty to sixty frames with video and audio then you might well be able to crack this. Depending on how frequent these lockups are you might be able to make these catchups less frequent but the Deck seems to need tearing for stability. Congratulations on getting verified back! I'm hoping the advice here will help you keep it. And congrats on 25 years, it must have been an amazing journey.
