I found in service menu (engeener section) BT_AUDIO_ON_OFF - default was OFF, I changed it to ON and than Sound -> speaker settings menu I can use bluetooth headphones - just like on attached screenshots.
I connected my headphones but after connection was silent, but when I switched audio into TV speaker and again into BT it is working

Can someone test it on another models my is 48h6500 T-MST14DEUC 2130.0