There is some branded companies also started making the iPhone 11, iPhone Pro Max cases for the phones to protect their cameras and body.
Here is one - On White iPhone Strap Case (https://www.icasekart.com/product/on-white-iphone-strap-case/) I liked very much.

Some Specifications:
Wrist Strap Case For iPhone 6/6S
Matte Feel Phone Coque For iPhone 7/8
Hand Grip Coque For iPhone X
Ring Holder Fundas For iPhone XS
Soft TPU Casing For iPhone XR
Material:

Soft TPU Silicone
Pattern Case Cover Shell
Compatible Models:

iPhone 6 Plus, iPhone 6S/6S Plus, iPhone 7/7 Plus, iPhone 8/8 Plus, iPhone X, iPhone XS Max, iPhone XR, iPhone XS, iPhone11, iPhone 11 Pro MAX, iPhone 11 Pro