Dedicated machine? Linux is free. Perhaps the privacy issues are not so important on a dedicated crunching machine. I don't know of any reliable performance comparison studies on non-Vina projects. Consider that there may be some bias on opinions regarding performance when there is not a reliable scientific method cited. Is linux supported on all projects currently and likely to be supported on all future projects? But, could always switch to Windows if a desirable project wasn't supported by linux.

If your CPU is common enough, you may use the results of the WUProp project: https://wuprop.boinc-af.org/ Maybe consider contributing yourself.
Linux seems to be best option for dedicated machines (although the concept is somewhat questionable, unless you are using electricity for heating).

My hall and kitchen is unheated, the only option would be an electric space heater.

So I opted for 3 dedicated BOINC/F@H rigs instead to keep it cozy in the winter

I turn off all machines except a single 80W cruncher when the heat is not needed. During summer everything's off.

You can minimize the enviromental impact of crunching, even though research is one of the things I think we should expend a lot of energy on.

Linux is better because it uses significantly less overhead on modern versions compared to their windows counterparts. Plain and simple. Network is essentially OFF unless it's being used (from what I do), but beyond basic drivers support is abysmal. If you're running on a prebuilt machine that has Windows keep it. Otherwise Linux over an Ethernet connection is the way to go.