I had created a systemd service to put the board in suspend to idle. This freezes all processes and shuts off all CPUs except CPU0. It does require an IR power scancode to wake.
If your remote has both BT+IR functionality and the box has an IR receiver it might work for you. The SEI remote falls back to IR in s2idle, IR can then wake, and the remote repaired by BT.
Otherwise, the service might give you some ideas for your setup.