Why is my MacBook Pro showing Exec + >_ + Exec?

I cannot translate the labels on those items, but I suspect the system was hacked to run an unsupported version of macOS.

You will either need an OSX 10.6.x Snow Leopard upgrade DVD, or you will need access to another working Mac generally from 2007 to 2015 in order to create a bootable macOS 10.11 El Capitan USB installer using the instructions in the following Apple article:

Create a bootable installer for macOS - Apple Support

Make sure to also carefully read the linked article within that article for the instructions of downloading & extracting the El Capitan installer since there are multiple required steps before the real El Capitan installer appears in the Applications folder so that you can then create a bootable USB installer.

You can confirm the other Mac is compatible with El Capitan by using the information in the following article:

https://eshop.macsales.com/guides/Mac_OS_X_Compatibility

In order to boot the installer & use the correct version of macOS on this laptop, you will need to perform a PRAM Reset to clear the customized PRAM/NVRAM configuration used by the "hack" since it seems to prevent proper versions of macOS from booting. It is best to hold the PRAM Reset for at least three chimes to ensure the PRAM/NVRAM has been cleared.

Looks like "BootKicker.efi", "OpenShell.efi" and "Reset NVRAM"...definitely an "OCLP gone wrong" problem and your reinstall advice is the best way ahead.