Hi @electrum thank you for your post here on the Zoom Community! The spotlight feature only impacts the video or video screens that people in the meeting will see. It does not impact the audio piece or having someone be able to mute themselves.
Now, if the host has muted all, they can check a box to allow participants to unmute themselves, or not. If the host is not allowing people to unmute they would not be able to and perhaps that is a factor in your scenario. Some more information on muting all https://support.zoom.us/hc/en-us/articles/203435537-Muting-unmuting-participants-in-a-meeting
If this has answered your question to your satisfaction, please click the "Accept as Solution" button below but if not please reply and we can continue the discussion. Thank you!