Use only Ethernet or Repeater

If I have connections for both Ethernet/Repeater, if I manually disconnect Repeater then my Ethernet connection will be used. To force the Repeater, I both have to pull the cable and enable the Repeater.

Is there not a software version of this? And more importantly one which will take the Ethernet when it has a valid connection and use the Repeater only as a backup.

What is the use case for that?
Is repeater and ethernet connected to the same network?

No, different networks. Main and backup as it were.

Sorry I cannot really understand your question.

Do you mean Mutil-WAN?
If WAN have 2 interfaces, like cable WAN and repeater, WAN as backup, Repeater as main, when the repeater down, the WAN will be work. And the repeater always still in scanning, if it re-connects back, router will back to repeater interface.