Custom Binary Blocked by FRP lock, red text on bottom right of screen will occur on reboot / turn on as you have said when OEM unlock is not enabled and is set on disabled instead.

To get past that you’ll need to reflash a stock Samsung Rom (Match phone model SM-G928x) that is at least the same or newer version firmware back onto the phone. You’ll end up losing all data as if you have flash root / custom recovery files before it means that the data on the phone was setup as not being encrypted and when you flash back a stock rom it enforces encryption so it wont let you boot the phone up normally without factory resetting / wipe data the phone afterwards in recovery mode.

It is possible to remove FRP lock to let phone boot without factory resetting it / flashing with the use of a gsm flash box like Z3X tools but that costs money to get.

You can download firmware using either of the 3 options:

• Download from Sammobile.com
• Download from Updato.com
• Download with the use of the program called SamFirm