Mac Book Airs, at least recent ones, don't have the optical output. What I would do is one of two things-if you don't want wireless, get a Schitt Modi, which accepts usb inputs. I'm not a Mac guy, but you may need a USB C/USB conversion cable.
https://forums.stevehoffman.tv/threads/digital-audio-out-from-2019-2020-macbook-air.943564/page-2
Option B, if you want wireless from the Mac, get a 2nd gen Airport express (on ebay, 50-60 bucks). Later than 2nd gen lack optical out, older only do 2g not 5g. Run an optical cable from the express to the Schitt. Play music on the Macbook and stream to express using airplay. I do this from my phone to 4 different audio systems in my house and it works great.