Hello, I was expecting my other tester to reach me, but he didn't. Anyway, I have good results at this point. My Convexa-S haven't crashed in more than 8 days. My EA6350v3 either, but there was a power shortage, and I can't be 100% sure about it. My Convexa-S didn't reboot because it is connected to a UPS, white the EA6350v3 is on the second floor (without a UPS).
Anyway, I have uploaded the files to GitHub under the v2.06, so anyone interested can check it out.
If what @fdm says is true (I haven't done the research yet), it is actually quite sad to know that the device is likely unfixable. I didn't want to give up, but I see no further room for improvement at this point if that's true. Maybe an ath10k guru can help, but it's certainly beyond what I can do or know.
Proof that my Convexa-S is "stable":
