I believe it is possible to run VST's in a 'systemwide' mode on Windows, yes. From a quick Google search, I'd look at an application called Equalizer APO: https://equalizerapo.com/ This app is itself a systemwide equalizer, but it can apparently also run third-party VST's, so you should be able to use it to run something like the Pro-Q 3 in Windows. You do not need any hardware DSP, in my opinion. I use RME's hardware-DSP based equalizer, but that is only because I use both monitor speakers and headphones, and I want the EQ to apply only to the headphone output. For that reason, a systemwide VST doesn't work for me (it would apply the same EQ to my speaker output).