Bought my cat a nice and large bed which is more akin to a throne but anyway. He now happily sleeps directly next to it.

The level of interest a cat exhibits in a toy is inversely proportional to its price.

Unless it's something you bought for yourself rather than the cat, in which case the cat goes for the most expensive thing first.

Fully subscribe to this take.

But in all seriousness, I think I underestimated just how much cats rely on smell at all times. I noticed yesterday that this plushy polyester bed is still strongly smelling like plastic mixed with some random pet store odors. This is likely not helping.

I will laundry it at 60 degrees Celsius as recommended, sprinkle some of his cat hair around it and then see if he finally accepts it. At the moment he still prefers sleep on (multiple) electronic devices and on the floor in the hallway between rooms (attacking anyone passing by).

There are a couple of them which offer selectable force of the fountain effect (e.g. https://www.chewy.com/petlibro-stainless-steel-dog-cat/dp/37...), so it may be their domestication has tamped down the "babbling stream" identification circuits and they need something a little softer

I'd also be on the lookout for the electrical hum mentioned in TFA; that would drive me crazy, and I can't speak to how it would make any kitty wary

Also, and this may go without saying, but watch out for the fountain(s) being made out of materials which are hard to clean