DFU is a bit finicky to set, try it a few times. Here is a pretty good video on how to set your iphone in DFU mode : https://www.youtube.com/watch?v=kaRpv3sjaHU&ab_channel=HardReset.Info Also do not try to reinstall the update on your iphone, tried it but the same bug occured again

there is a comment that said that they used the DFU mode to recucitate their phone but it is possible that it wipe your data, i will pinn the comment for the moment if you are intrested and would like to take a look