You can remove the heat spreader, AKA delidding the CPU. It's a significant bottleneck in cooling modern, power-dense CPUs like this, if you're relying on a fluid at ambient temperature.
Yep, the venerable de8auer channel has confirmed this does allow the P-cores to run 6GHz continuously at ~75C:
For the real heroics we'd need cooperation from the manufacturer. Such as using monoisotopic diamond as substrate or putting some channels for liquid helium into the chip.
Things that are not liquids at 1 atm of pressure. Liquid helium, liquid nitrogen, etc.
You can run a water chiller, but managing condensation gets tricky.
Closed loop helium gas cooling system = lots of gigahertz