Hi,
Your computer?
Motherboard: manufacturer and model?
CPU: manufacturer and model?
Graphics card: manufacturer and model?
RX 6900XT does not tell us what type of card it is and who made it, manufacturer and exact model is required.
Graphics driver version? for example Amd Adrenalin s/w 22.4.1?
Latest driver here: https://www.amd.com/en/support
PSU (power supply unit): manufacturer and model?
Here it is important to know how many Ampére on the 12 Volt rail it can handle, as well if it is a single rail?
How exactly are Your 12V PCIE power connectors connected to the graphics card?
You got 2, right, but if it is not a modern single rail PSU, then You don't want to use a daisy chain (shared dual 12V PCIE connector on the same cable) instead use a second separate 12V PCIE cable from the PSU PCIE connector to the graphics card.
I recommend this anyhow since it will minimize the risk of voltage drop on heavy ampére load when the wires get hotter - which they never should be.
First: make sure that the graphics card is properly seated in its PCIE connector on the motherboard, Yes this is not a new fenomen.
Second: Make sure that the two PCIE 12V connectors (separate cables) from the PSU is really plugged in correctly to the graphics card connectors.
yes, this is also something that can cause the issue you are having, because the graphics card does not have proper power supply.
Best regards from Sweden