Similarly to what happened with the Galaxy S10 One UI 3.0 update last month, users across the globe are saying that the One UI 3.1 update meant for the Galaxy S20 FE is no longer available. There's no official statement on the matter from Samsung but people think that it might be due to the various performance issues some owners are experiencing after updating. Battery drain, unreliable SMS notifications and general slow-downs have been mentioned on various online boards. So far, the update has been distributed to the majority of European countries but, of course, it's now no longer...
Source: https://www.gsmarena.com/samsung_pulls_the_stops_of_the_galaxy_s20_fes_one_ui_31_update-news-47724.php