How to add SPDIF and Toslink connections to my computer

My motherboard lacks SPDIF and Toslink connections.  I don’t want a sound card, or at least I don’t want to USE a sound card.  I want to buy an external DAC.  I can use the computer’s USB connections with my as yet chosen DAC, but most have a micro USB, particularly the ones I’m interested in, and I read they are less desirable for audio quality.  Is there something I can add to my computer, besides a sound card, in the way of a card or adapter to get those connection.

This is for my husband’s computer.  His old computer went down and the problem could not be easily diagnosed so he bought a used Dell.  A pathetic substitute for his previous Intel motherboard, but it is what it is for the price.  Next to it sits a Meridian 551 integrated amp and a pair of Spendor S3/5 speakers and we got decent audio from the old sound card, an ASUS Essence STX, but not great and  I want better if I can get it.  So moving from a sound card to an external DAC seems like a good idea.

I’ve been looking at USB DACs like Schiit Modius, Allo Revolution, SMSL Sanskrit.  Basically DACs under $500.
ideas welcome.