That’s not always true, it depends where you place the AIO radiator, some ITX case for example perform better that an aircooler because the heat is transport somewhere else.
What most people do is place the radiator at front of the case and blow the hot air inside the case, yes then there is no advantage.
I would purchase the K edition and not the Kf for troubleshooting purpose and also if you mainbord can do it you have switchable graphics like a notebook does, in Windows it’s run on iGPU and at gaming the dGPU.
KF is usefull if you want to heavy overlock.
Just hit Scroll Lock to temp disable e cores.
I would do at least 280mm because the noise.
Check also single vs dual rank memory.
For troubleshooting purpose don’t take a F serie.