Samsung is reputedly sticking with a 4,500 mAh battery capacity for this year's Galaxy S21 FE. The Galaxy S20 FE has the same capacity, but the Galaxy S21 had to settle with a 4,000 mAh battery instead. Hence, the Galaxy S21 FE may outlast the Galaxy S21 in battery life tests.
https://www.notebookcheck.net/The-Samsung-Galaxy-S21-FE-set-to-retain-the-4-500-mAh-battery-of-the-S20-FE-giving-it-an-advantage-over-the-Galaxy-S21.535329.0.html
Please Samsung if you are listening bring back the headphone jack for the S21 FE