A Custom os install warning.

I have a Samsung A32 5G. i replaced the screen for it and as soon as I did the first boot I am given a popup of A custom os has been downloaded and has some critical errors. tried restarting the phone but nothing. only 3 options vol up for continue, vol down for cancel but it will erase all the data and side key for menu. my vol down option is not working. and I am stuck.