I have the original A95X Max an have it working well and although yours is an S905X3, whilst mine is S905X2 I do know about the box not switching off…
To cut a long story short, once upon a time the DTB for the box worked fine but following an update, every time that I tried to shut down the box it just rebooted.
Investigation showed that there was something like a 1 byte difference between the old and new DTB but other than that, nobody could see any difference.
But when I extracted the old DTB from an image and replaced the new one, shutdown worked correctly.
So every time that there is an update I just replace the new DTB with my older working one.
Now my DTB is not going to be of any direct use to you because of the differing SOC’s but based on the fact that the boxes are from the same generic manufacturer line does make co-incidence less likely.
One for the devs, although worth noting that because this is a new box there may not be a specific DTB or it at all yet as nobody may have asked for one.
As for the VFD, there is a thread here.