That's quite focussed on the PC use case. Trickier to also incorporate the AirPlay feature that the OP wants as well as a PC hook-up with that solution.
These are the ones I use: https://www.ebay.co.uk/itm/15398445458
I have the above cable plugged into this https://www.tindie.com/products/beni_skate/automatic-spdif-opticalrca-audio-switch/ the RCA end, with the XLR connected direct into the AES/EBU socket on the Genelec. I then use a regular...
For reference: https://support.genelec.com/hc/en-us/articles/360019582539-Can-I-connect-my-digital-SAM-monitors-to-S-PDIF-directly
I've tried with and without impedance convertors up to about 5 meter cable lengths. Both methods work fine, so I got rid of the impedance convertor.
The Douk Audio U2 is an excellent and inexpensive USB to SPDIF that you can use with your PC: https://www.audiosciencereview.com/forum/index.php?threads/phiree-u2s-2019-douk-audio-u2-review-and-measurements-digital-usb-to-s-pdif-interfaces.29765/
This is a fantastic SPDIF switch you can use...
With my 8340As in my kitchen, I use SPIDF:
- a USB to SPDIF out from the iPad and Laptop
- the SPDIF out from an AppleAirportExpress (for AirPlay)
I feed both of those into an SPDIF switch and feed the coaxial SPDIF from that switch direct into the Genelecs. Works great and very cheap.
If Genelec SAMs, or other active speakers with an AES/EBU input are an option for you, then I find this works well between a Windows PC and the Genelecs SAMs: https://rme-audio.com/hdspe-aes.html
It's got 16 AES/EBU outputs, but I've only used 6 of them, so can't comment on the >8 channel...
They can take a while as he makes them to order. Took a couple of weeks for the two RCA ones to arrive in the UK. I'd give him a nudge if you've heard nothing :)
The BNC variants take much longer as he batches them up. Took about 6 months for my BNC one to be made & shipped to me.
Here's the direct link to the RME recommended SPDIF switch, in case anyone missed it in that forum thread: https://www.tindie.com/products/Beni_Skate/automatic-spdif-opticalrca-audio-switch/
I have 3 of them and they all function well. Never any drop-outs etc. I never use 192kHz sample rate...