OpenSUSE on Desktop, macOS for laptop. I’ve used macOS on portables for years now but only in the last 3ish months have I gone the linux Desktop.
As to the “why” - macOS because it’s polished, tightly integrated with the hardware, the ecosystem works harmoniously, it’s secure and Unix-based (Darwin is the name of the base OS used for both macOS and iOS).
For Desktop - I used Windows pretty much all my life but it’s gradually turned into a bloated advertising and tracking engine. I’m speaking as a home user and a 10+ year IT professional. Linux has come in leaps and bounds and OpenSUSE is an enterprise-grade OS that also happens to run games and other personal things nicely. If I wasn’t using it I’d probably be using Red Hat but I dumped it largely due to their shitty business practices.
A couple I’m aware of are Parsec and Moonlight. Parsec is a bit more polished and user friendly I think, but Moonlight is open source.