[Tildey]

I have a USB switch, my keyboard and mouse go into the USB hub on my monitor, and that hub is switched between my laptop dock and my windows pc. The monitor input is changed on the monitor. A proper KVM would be easier but is also many times more expensive.

I use my laptop open though, so I can still control it when using the windows pc.

For audio, I use a simple 3.5mm splitter. They work in both directions, so with the right combination of male/female 3.5mm cables you can merge the audio for about $10. There are fancier audiophile solutions too.

Something like synergy (from symless, there are competitors and FOSS alternatives but I can’t remember their names) might be good for your use case, to carry over m/kb input to the non-windows machine.