Is there a setting to do it? Otherwise, in many situations viewport FPS drops below the target rate, and audio track (added through Video Sequencer) goes out of sync, making impossible to animate. I understand optimization, but what if I do not have time to make lowpoly proxies for characters, or have to work on weak PC?
Did you look in the Playback Menu in the timeline?
You can set characters to wireframe or bounding box.

Keep in mind that you can select a number of objects, and as long as one is the active object you can hold down the Alt key while changing the Display As option to change all of them at once.
If the characters have rigs then hide the character. The rig alone has much faster playback.
You can also hide everything, play the audio and in the timeline press M to add markers at all the important audio points. Then animate to the markers. Doing this anyway can be really helpful because the markers show in all the windows that show the frames/timeline. Or add markers on the waveform peaksā¦
Playback - Sync - Frame Dropping is what I was looking for. Thank you