I just recently tried that myself (Sennheiser Momentum 4 + Sennheiser BT T100) and for me its fine when ‘playing’ sequencer, and I cant honestly notice any delay on movies, etc, but its completely unusable for playing keys, so I suppose anything really live. the latency is suddenly very clear, annoying, and I couldnt even properly play stuff I know well, as the disconnect between pressing the key and the sound was quite confusing…