before you are trying to fix this issue, make sure you have uninstalled all the Google related apps: Google home, google maps, google classroom, Gmail, Chrome, youtube, youtube music, youtube kids, Family Link ... Nest, Linkedin (even this is from MS, but it will trigger the Play protect error) ... and there are much more that I cannot list them all. If any of residual apps exist, that will 100% lead to failure. I know it is hard to uninstall all of them, i made this mistake all the time, and then later on found out that some hidden app stayed in the phone, which i would need to do it again and again. Therefore, factory reset is always the best to ensure a clean system, but i also understand it is hard for people to reinstall everything and re-login all the accounts.
Another possible reason is: the google play service version, there was an update last month, and so far i found Play Services 21.18.15 is the last good and stable version. you can use that instead of 05... file from the preparation files.
drive.google.com
or
1drv.ms
i hope this note helps.