As these are fixed lugs, I'd put a single piece pass-through leather strap(one piece NATO, I think they're sometimes called).
For something more casual, maybe a brown or dark olive perlon? (I am a fervent apostle of the gold+perlon combo)
Example: https://omegaforums.net/threads/perlon-nylon-6-wrist-watch-straps.102738/#post-1342594