looking like an old PC with an old soundblaster card may be your best bet.
also Mac Mini’s have optical in as well as out, cheaper than some of the pro audio gear to find an old (e.g. 2009 vintage) mac mini, they is a combo 3.5 mm and optical in a single connector - optical / coaxial converters are cheap on amazon.
Alternatively if you don’t want to spend big, just use the analogue out. as @Elk says this is not “purist” but will work, and probably sound fine…