This works pretty well for me, I have it running some old Infinity speakers for my rear surrounds:
https://www.bestbuy.com/site/rocketf...?skuId=8275528
It's not super awesome or powerful but it's just the rears so I don't care much. Just have to give it line-of-sight and you're good to go.
I'm not sure about the other. Generally, receivers don't have optical outputs to connect to a soundbar, since they are intended for powering speakers. The A/D converter may work, I've never tried one. Been out of the game for a few years.
Optical splitters exist but I can't vouch for them. Maybe you could take the TV output, split it, and run that to the soundbar and the receiver both?
Example:
https://www.amazon.com/ViewHD-TOSLIN.../dp/B00G191YL8