I was getting so frustrated with the camera on my S21 ultra. I'd hit the shutter button and about 1-3 seconds later it would take a pic. I was frustrated to the point of wanting to switch phones.
The tip I found was turing off scene optimizer, shot suggestions and QR scanning. The lagg is gone.
I hope I can help someone else (for some reason it took a while to find that advice when googling).
