Turns out I was smart not to upgrade to the newest FW =)
I sleep peacefully!
While I cannot help you, I do want to say that it is shocking to me how many people use the rotate screen feature on the DX300 MAX. It's such a massive and heavy DAP, I would've never imagined anyone uses it horizontally... Turns out I'm wrong.
In terms of the screen, I'm very skeptical about that, because I do have the DX320. If I didn't have the DX300, I wouldn't be able to say this, but the DX300 has the most accurate colors and the greatest dynamic range. The new DX320 has overly saturated colors, imo. I'm scared that it's Android 11 doing this, but can't confirm.