The problem is not in your setup. The problem is in AMD and its infinite incompetence.
They can't cool or even try to cool a 200-250W card with this tiny heatsink without a single heatpipe, and with an awful turbine which is not suitable for cooling so power consuming GPUs.
The copper baseplate is a heat pipe unit which spreads the heat into the 3" square copper plate. The black part of the cooler is also metal and has contact pads with hot components. The issue I see is that the fan is not big enough. Maybe a fun mod would be to remove the stock fan, 3d print an air funnel and use a Noctua to force air through.....