Reviewer Random Stuff 2 on Youtube managed to play with the upcoming Samsung Galaxy S21 Plus for more than a month and included his impressions in a short video. He specifies that the reviewed unit is a pre-production device, so some things could differ on the final product, but even so, the phone may be one of the best models of 2021.
https://www.notebookcheck.net/Samsung-Galaxy-S21-Plus-unofficial-review-surfaces-almost-1-month-ahead-of-launch.510366.0.html