I did some research on how to update ui version but the way they do it is I don't have that, I saw some people who have updated their S20 Fe and I always questioning to myself why I can't update. I got this on June 13, 2023 my relative gave this to me.
device: S20 Fe 5g
model version: SM-G781
current android and ui version: Android 12, one ui 4.1
Prior to your acquisition, the device has been restored to factory default, correct? I'm not sure if your unit is eligible for One UI 5, but if scanning for the update manually doesn't work, you can try connecting your device to a PC and updating via Smart Switch. I also read that some users have taken their units to a service center so they can perform the software update from there, but I haven't tried this service yet so I can't attest if this is possible.
