Hi there and welcome to the community!
There’s a couple of us working with NUCs and mini PCs - there’s a whole thread on that topic:
https://community.cantabilesoftware.com/t/mini-pcs-nucs-update/
I’m currently running two ASRock DeskMini setups (main and back-up), one based on a Core i5 (9600) and the other on a more recent i7. Both run very nicely somewhere behind me, with a simple touch screen on a mic stand all I need to operate. Not quite headless, but good enough.
No useful “internal” audio interfaces for that form factor, but plenty of small-size USB options in all price ranges, depending on your budget.
I’m running a larger setup based on an RME Babyface (and a separate multi-output ADAT I/O box), and a smaller, more portable setup around a Zoom UAC-2. Both excellent in terms of low-latency performance.
Hope this helps!
Cheers,
Torsten