You might want to take a look at this article, just came out today, which pits the Samsung S21 vs. the Pixel 5a. I understand the S21 isn't exactly an S20 FE, but I still think the article is useful to you.
https://www.tomsguide.com/uk/face-off/google-pixel-5a-vs-samsung-galaxy-s21
I did not think it was fair to rate the S21's battery higher than the Pixel 5a since the only way to get S21 in Pixel's endurance range was too throttle down the screen rate to 60 hz, something that I doubt a Samsung owner would do.