I am running Libreelec 11 on an Rpi4 and was having the same problem as the OP.
I changed the docker image from 'http://lscr.io/linuxserver/homeassistant' to the official 'homeassistant/home-assistant' and the bluetooth was immediately recognized and Home Assistant began discovering devices. You still need to add the volume '/run/dbus:/run/dbus:ro' to you docker command or docker-compose. The issue seemed to be with the image.
Just figured I would contribute my solution to this issue since the OP stopped replying.