Catalina update failure
Mid 1012 MacBook Pro running 10.15.4 functioning normally with an EFI password and attempted an update to 10.15.5. During update my mbp seemed to "hang", so I left it to finish the update. When I came back to it it had a grey screen with a flashing folder & ?. Tried restarting, same result. Other things I've tried: cmd-r, option-cmd-r, option, reset nvram, reset smc, d, option-d, safe mode, and much more. I was able to get a screen showing the drives and tried selecting each one of them, however, they all resulted in the flashing folder & ?. Created a usb boot drive, selected it, resulted in a grey screen with globe, triangle !, apple.com/support, -2100F. Nothing I've tried will allow the update to continue or allow my mbp to start up normally as it did before attempting this update. Any suggestions?
MacBook Pro 13", macOS 10.15