Hi there thebartez,Hello.
I have found the solution!
I own 706 oled, bought another philips remote control that looks similar but has full functionality (YKF474-B001). The trick is to spawn accessory pairing interface that has been stripped from settings in this tv model.
I was able to use tvQuickActions to program whatever button you choose to spawn that pairing screen. As an action use APP -> Settings (hold ok for couple of seconds to choose activity) -> AddAccessoryActivity (com.android.tv.settings.accessories.AddAccessoryActivity).
After finishing the pairing process everything started to work (voice search, google assistant, etc.).
One thing though, while pairing process, after it will initially pair, i had to 'connect' one more time to PHRCL using other remote.
Wondering if you could help, I got the remote and followed your instructions and it works a charm. However it drops the bluetooth connection after a while. Have you found a way around this ?