Place it just after the confusing line in your edit, then follow it with a short huh before the speaker tries to explain again, and save a wait-wait reaction for the moment that second explanation gets even stranger.
Über diesen Sound
This seven-second clip is a French voice asking, in disbelief, what someone has just said, as if the words refuse to make sense. It lands as pure confusion, the sound of a listener lost mid-conversation and trying to catch up. The baffled tone makes it feel immediate and relatable, like hearing something so unclear you have to ask again.