Upgraded to Xbox One S now surround sound no longer works (0x80bd0009)

I fixed the issue!

I'm gonna post exactly how it went down in case somebody comes across this in the future

Like I said earlier I discussed with Xbox devs and concluded that this is an issue with my TV. I did extensive (10 hours worth) research and found these resources that helped me immensely:

LG EF9500 Semi-Idle based dimming? - Page 2 - AVS Forum | Home Theater Discussions And Reviews

New LG TV's and 5.1 pass through | Sonos Community

Amazon.com: Lg - Zenith Nec Service Remote Part # 105-201M: Home Improvement

In Start menu for 2012 LG's · Issue #9 · ubaransel/lgcommander

Access hidden service menus / modes - Openlgtv

LG 55EF9500 and 65EF9500 OLED Owners Thread - Page 393 - AVS Forum | Home Theater Discussions And Reviews

I got the service remote from the Amazon link and went to EZ_Adjust menu -> password 0413 -> Tool Option7 -> EDID_TYPE and changed it from PCM to DTS. After this I turned the TV off using the service remote, waited 15 minutes, and turned it back on. It displayed "WebOS" as it did a full reboot. After that I was able to adjust to Bitstream out in the Xbox settings and get 5.1 Dolby Digital (yes it's weird that it had to be DTS earlier)! It does have some audio sync issues though, I'll try to solve it.

EDIT: ok I changed the EDID_TYPE to AC3 and rebooted and it continued to work. In fact the weird little audio sync issue I was getting! Now it's 100% fixed.