Have you tried other cables/molex connectors from your PSU?
As for your D5 NEXT's problem, typically it is enough to make sure that your Windows power plan do not allow to disable USB connections. When your pump loses software sensor, most likely its because it is losing USB connection.
Also there are known USB problems on AM4 platform (seen messages with problems on X470 and X570) due to AMD USB drivers.
I have tried a different cable & molex connector, that was my first guess, without any change in behavior. As to the AMD, I'll look at those messages. I'm using the TRX40 platform, but the point is well taken, thank you for pointing that out, I wasn't aware. It's odd that out of a large array of USB devices, only the Aquacomputer ones have issues, and it's several Aquacomputer devices that have consistent problems.
Sebastian, I'd love to update to x.32, but according to the download and to the Aquasuite update screen, x.31 is the latest it's aware of (I've got insider versions checked.)