The Galaxy Tab S7+ (or Plus) is a 2020 premium Samsung device with an AMOLED display. Unfortunately, as such, it has reportedly run afoul of the "green tint" issue. Some customers claim to have faced this on-screen blemish for months, and that the OEM has yet to push a definitive solution of any kind as yet.
https://www.notebookcheck.net/Galaxy-Tab-S7-owners-are-still-reporting-the-green-tint-bug-and-that-Samsung-has-done-little-about-it.536307.0.html