Complaining about a teacher to other students changes nothing. Talking to the teacher sometimes changes everything.

Complaint aimed sideways feels productive because it gets agreement, and agreement feels like progress. It reaches everyone except the one person who could adjust anything, so the situation stays exactly as it was while you get steadily more certain about it. Going directly is worse in every way except the one that matters.

Ask for a few minutes after class and bring one specific thing rather than a general grievance. Say what is not landing for you and ask what you could try. Most of the time the conversation is shorter and less hostile than the version you rehearsed.