Do you need the data on your phone? If not, try to get into the bootloader and do a factory reset. Otherwise, connect you phone to the PC and use a program like [https://www.techwikies.com/apps-for-pc/oneplus-switch-for-pc-windows-mac/|OnePlus Switch] to try and backup your data. It looks a bit to me like the proportions of the buttons aren’t completely right, which may have occured due to the LCD/Digitizer replacement.
If you have any more questions concerning this, just post a comment!
Carpe Diem,
Minas