I'm looking for recommendations on the best AIO liquid cooler to keep this beast running cool and quiet. Any good recommendations ?
For that processor, opt for a 280mm or 360mm cooler. While a 240mm might work, it'll be constantly strained. A 280mm AIO is the safer choice, providing better cooling performance without excessive stress.
Consider the Lian Li Galahad 360 II - solid performer at a good price point. The 360mm rad is what you want for the 13900K's heat output. Make sure you've got good case airflow too, as these chips run hot regardless of cooling.