My situation is not better than yours Henry, my setup is to connect to an older version of Sony projector which has no ARC or eARC. However, I am using a Pioneer receiver with Dolby Atmos and DTS:X codec on board but in this case my receiver is just used as a AV switcher with the on board DSP in bypass mode. The following is the connection in this setup:
Apple TV 4K/PS4/WII/Bluray player to HDMI input on the Pioneer receiver
then from HDMI output to JBL Bar9.1 HDMI IN
then from JBL Bar9.1 HDMI out to the projector HDMI in (your case TV HDMI in)
Make sure you set the JBL in HDMI in mode not TV mode.
High quality soundbar and it is definitely not an entry level soundbar. I am still trying to figure out how to display video via airplay on my projector, audio is working fine but not audio. If you know please give me your two cents. In near future I will get a 5 to 1 HDMI AV switcher to replace the receiver so than I can use the receiver somewhere else in my house.