No prob, i'm glad to be helpful. 🙂✌️
Now, i don't know of any sound card that uses USB as an output, so yeah, SPDIF would be your only option.
And yes, all X-Fi cards have Windows 8/10 official compatible drivers. They were the *top-tier sound solutions of their time after all. 🏆🎵
*Except the X-Fi XtremeAudio, that thing is just a re-branded Audigy SE.