I haven't tried the Phoebus, However i have the Essence 2 and Windows 10 x64 Drivers install fine and work flawless on 11.
I can see the Phoebus does have 10 Drivers so give them a bash, Id say they would work.
As for you're on board sound question They have gotten better as newer boards come out with better sound chips, But they still imo don't come anywhere near a proper good high end sound card.