I have the cooler on a Threadripper 1920 (180 Watt TDP). The cooler is just enough (especially the cooling plate is a bit small for the Threadripper, so overclocking is not an option).

Consequently, the cooler should have no trouble with the Ryzen 9 5900x (105 Watt TDP). Even overclocking would probably not be a problem. The Ryzen 9 is also physically smaller, which means that the cooler will achieve better efficiency.

Personal opinion on a water cooling AIO: I replaced this cooler with a Noctua air cooler, as it is quieter and reaches slightly lower temperatures on my CPU. A good air cooler is usually as good as a water cooler (as long as overclocking is not a goal) and much more robust and low-maintenance (I haven't had any problems with the water cooler so far, but they will come eventually). An air cooler lasts forever because there are no wearing parts such as pumps, seals and hoses.