hello everyone. i am going to try to walk you through with what exactly happened. i was trying to update my iphone 6s+ to ios 14 beta 1 and no matter how hard i tried it never updated and finally my iphone bricked and i had to restore it to 13.5.1 but before that i am pretty sure that i made a backup on my windows 10 laptop. now my primary drive C:\ shows that i dont have a lot of space left cus i made a back up but i cant find it and neither can itunes. my exams are coming up in a few days and i had of stuff in the back up. please help me out here.

can someone please tell me why cant i update my 6s+ to ios14? everytime it downloads on my phone and my phone restarts for the upgrade it take a minute or two and my iphone goes back to the lock screen. i even tried to upgrade through itunes using ios 14 ipsw but to no avail :( ps i have good 8 gbs free on my iphone