Connecting Bose soundbar for best sound

What is the best way to connect with a Bose sound bar to get the best sound from the box?  1. Should I connect an eARC cable directly from the XFinity box and run a separate video cord (optical or ???) to the TV from the box?  2. Should I connect a cord from eARC (Xfinity box) to ARC (TV) and then run HDMI from TV to Bose? 3. Is there a better connection from box to TV and then  HDMI (TV) to eARC on Bose?

[Bose wants me to connect from TV to soundbar but I don’t want to diminish the sound with a TV “middleman” if the sound would be diminished. I have a Bose 900 soundbar (with Atmos) and a Vizio (TV).  I would like to run all sound through the Bose.  I also cast my computer to the TV, so I would like that sound to go through Bose too).]