Performance - dGPU - 3DMark Time Spy
Performance - Games - Radeon RX 6600M - 3DMark Time Spy
3DMark includes everything you need to benchmark your hardware. Time Spy is way more GPU-dependent, though. But still, a very representative title concerning PC gaming performance.
Since the 6600M is not an IGP, but rather a dedicated card mounted into the PCB, we need to compare it with dedicated cards; I have to say for a mobile 6600, it's performing exceptionally good, within 10% of the actual card.