Google Pixel 2XL Cameral Cover Replacement
https://www.youtube.com/watch?v=tOeJ_Q1QcgQ
Used these - [1]
Note the tan rings are the double-sided adhesive. Take off large backing, stick to back of lens. Front side of lens is uniform. Take a sharp point and take tan backing off the other side of adhesive. Then only the black-looking shiny glue remains on lens. Attach lens to camera.