As far as I know, there is also a hardware compression unit. But I really don't know why they need it. If a game is paused and saved into memory, they could use the CPU that is not used in that moment by the game. But it might need a little bit longer.On load time, I tested quick-resuming Control: Ultimate Edition and Gears 5 into empty memory (i.e. no game running), both takes around 3.5s. And that's probably uncompressed since I don't recall them mentioning there's a hardware compressor.
Edit: Quick-resuming from Gears 5 into Control: UE takes about 7 seconds.