The Ryzen 7 5700X is a 65W chip, pretty easy to keep cool. I personally prefer air cooling (lasts far longer and easier to maintain) and would only seriously consider AIO water cooling for chips 125W and above. As long as you have decent airflow thru your case, and the P300 has decent fan mounts, you should be fine. As for noise, make sure you have a motherboard with fan profiles (or seperate fan controller). For example, I currently have a Ryzen 3 3300X (65W, PBO enabled) with an old Thermalright HR-O1 Plus with a 120mm fan clipped on. Fan stays at 40% (677 rpm) for 50C and under and up to 50% (846 rpm) up to 70C. Under CPU stress test, it plateaus at 71C. The same chip, with a Corsair 115i AIO, plateaued at 72C. Roughly the same. Although I have a pretty beefy NZXT case -- 6 120mm fans (3 front and 3 top), and a 140mm at the rear -- all mostly running 30-40%. Fans are whisper like audible, but is not unpleasant or distracting, though do intrude above 50%. As for a recommendation, if I were to buy a new air cooler -- would get the
Thermalright Peerless Assassin 120 SE. Is inexpensive and a top performer.