The Download mode screen shows
OEM LOCK: ON
While this remains you cannot install any Custom ROM.
Maybe after a Factory reset you did not re-enable USB debugging ?
The Easy Installer log looks OK; things progress OK, until wait-download.sh cannot complete. (As said already bootloader / Download mode is locked.)
There are a few words on the subject here Know your hardware – Samsung # OEM unlock.
This is a generic page for USB debugging https://doc.e.foundation/pages/enable-usb-debugging.
Any Google account must be removed. Often we find that the device needs to be online to lift some mysterious lock, please watch for that lock indicator to change if you get the phone online.
Edit Is the phone new?
The phone may be protected against a Custom ROM if you have not used it “normally” for a minimum of a week or two.
You might attempt “Check for Updates” within the existing Samsung UI. If remote monitoring applies this forces a connection.