I had a Sapphire Nitro+ RX580 before and +/- 85C under load should be considered normal. Idle temperatures are also fine.
Are you sure this isn't caused by a driver update?
If you keep error 43 a normal person is unable to fix the card.
You can try a lower clocked bios as last resort:
https://www.techpowerup.com/vgabios/265697/265697
Try to use AMD/ATI Pixel Clock Patcher. If the bios hasn't the correct signature, the drivers will not load and cause an error 43.
If the drivers do load after the AMD/ATI Pixel Clock Patcher then we know we need to find another bios. If you keep error 43, it is a hardware failure.
That is good to know, there are far less 1244mhz bioses :)
https://www.techpowerup.com/vgabios/264292/264292
https://www.techpowerup.com/vgabios/253652/253652
https://www.techpowerup.com/vgabios/263458/263458
https://www.techpowerup.com/vgabios/266536/266536...
Why did you flash the card in the first place if it worked fine?
Can you share the output of amdvbflash when the bios is flashed with the Shokings bios?
Can you remove the cooler since the bios dump of mihai333 only contains Hynix and Samsung support.
One small tip: Making a photo with phone of GPU-Z isnt a decent screenshot. Please use the screenshot function of GPU-Z itself in the future. I've explained it before how you can do it.
Can you try the following bios?
https://www.techpowerup.com/vgabios/263733/263733
I think it Shokings RX580 shares the same PCB. See the picture below and compare it with your card. The componments which are visiable are in the exact same spot and the markings are identical.