Water droplet in camera lens.

The problem will likely persist even after a long while of drying due to the fact that the Galaxy S21+ should have a water resistance rating of IP68. While the IP68 seal may have been compromised at a small point (otherwise there would not be any water ingress), it will take a very long time for all of the moisture to evacuate your device naturally from that tiny, localized break in the seal.

I would recommend following this procedure to take the camera out. You can then let it dry for a couple of hours or very carefully use a piece of paper to soak up the droplet, trying to limit the number of fingerprints and amount of dust that may fall onto the surface of the components.