THANK YOU @krl09! I can confirm your approach works 100%
After several calls to Apple (tier 2 support), with requests straight to engineering, no one was able to make "display" show up within SYSTEM PREFERENCES > KEYBOARD > SHORTCUTS. I bought a $15 windows keyboard and attached it to my MacBook Pro. I then followed the process above and "Display" showed up. I was then able to unselect decrease and increase display brightness from F14 and F15 keys.
I can now use the F14 and F15 key for something useful!
*** I will also add, this appears to be a permanent solution. I have since un-plugged the keyboard and restarted my MacBook. I can report that "display" still successfully shows shows within the process outlined above, which means I'll have the ability to select/un-select in the future if I need to ***
I have since returned the windows keyboard as this was all I needed it for.
I have to say, this was extremely frustrating and Apple engineering had terrible excuses as to why "display" was not showing, it was clear they didn't know why and were trying to hide/mask the issue.