@jay73
Yes, it's kind of complicated. There are a few dedicated transports more expensive than the Jays, and several less expensive. Each model has a different set of outputs. A good number of people use players as transports; some seem to work very well. There are long threads on the forum discussing the various transports currently available.
I'm pretty sure there are gizmos out there that will input one type of connection and output another. As I favor one-box players I'm not super-conversant with them. But take a look at this thread for starters.
https://forum.audiogon.com/discussions/i2s-s-pdif-toslink-connections