[Renate]

It would be interesting to find out what the exact problem is.
Reports of people watching videos seems to suggest the problem is overheating and loss of connections.
I have not seen a display and I don't know if is using regular BGA connections.

If somebody is completely desperate, has a fairly unusable device and Onyx won't help you might try to reflow the connections with heat.
Even if you get a temporary and small improvement but it's definitely there it will prove what's up.
But don't even attempt unless it's already a lost cause.