Remove noise from monitor speakers?

Hi!
I've been using monitor speakers for music production for about a year now. (Model: Focal Alpha 65 Evo)
Overall, I'm very happy with the speakers, but I've recently noticed a constant, low-level hissing noise, which I can hear even when I'm producing music or listening to music. It's a bit annoying.

Additionally, another noise occasionally occurs, which sounds even more "electronic" than simple noise and is also somewhat louder. It sounds strongly like interference.

Today, I happened to notice that this second noise appeared when my father plugged the car into the wallbox. I already suspected that the noise and the electronic noise were caused by interference, so here are my questions:

1. Is a certain amount of background noise normal in monitor speakers? (Loud enough to be audible even when listening to music)

2. Is it really possible that connecting an electric charging station could cause interference in the house's electrical system, resulting in noise?

3. Does anyone have experience with such issues and possible solutions to remove these noises?
– Could a UPS system that outputs a clean sine wave help?

Framework information:
The noise persists if the speakers are on their own circuit.
I also connected them to other circuits, but it didn't help.

The house also has a PV system with an inverter (could this possibly cause noise?)

Thank you in advance for your answers!