Pump has to be on to hear the difference- water running too- not likely to be the issue. Find the leak- it's there somewhere. The one in my Rialta was a tiny leak- doesn't take much to make the pump cycle. For now just turn pump off at night.
I added a SeeLevel system to my 20L (b/c BMPro is very unreliable for tank levels)- also has a pump switch, but needs to be changed to a momentary type for masternode relay, and I piggy backed wires off the rear pump switch under the rear wardrobe drawers. (send me a 'conversation' if you want more info on that) I placed on wall by bath so I can turn pump on/off at night w/o using app or BMPro. Much faster and more convenient.
Also could just be air in the line- so purge all outlets incl rear spray. Hot and cold.
If you look at the pump strainer, you can sometimes see air bubbles inside too if that is the issue.
Does the 2023 20L have a shower miser in the rear bath? (doesn't show on spec sheet- my 20L doesn't have that, but could be another place for air pockets)
drawer out as far as you can, then on the sides of the slides are black levers- one up and one down will allow you to remove the drawer. Click here:
Also make sure your bypass valves are set correctly- next to the Truma under drivers side bed access, near sink cabinet as seen here:
Cold and Hot open, and bypass closed for summer ops.
For winter storage after draining, Bypass open, and Hot and Cold closed.
