I'm sure it is long enough, Corsair does it pretty well for the last few years.
As a matter of fact, I notice that there are offset, just like the Meshify C, so it should provide sufficient clearance for the AIO(fan + radiator).
I obtained this screenshot from a video of the RL06. Judging by the eyes, there should be enough room for a 52mm AIO, what you reckon?