I am using 9800X3D with a puny AK400. Sure, at stock it runs just above 90C but didn't throttle in 15min or so extended Cinebench. With some UV, it stays under 85C at sustained load. For gaming, temps are 65-75C. My GPU is 5080, so 300W of power draw on that, so case is bound to be quite hot, still, no concerns. Cabinet is Lancool II Mesh, if you are wondering.
Again, I don't recommend AK400/AG400 to be paired with 9800X3D but an AG620 will easily suffice. Just don't overspend on AIOs when not required. Something like 9950X warrants a good AIO or even for Intel i7/i9, but Intel CPUs are not recommended after recent fiasco.