iTunes wants to backup local on pc when connecting iphone

Each time I when connect my own iPhone with iTunes my computer is selected in Automatic Spare Backup on my PC.

I have to be quick to unselect by selecting iCloud. If I hesitate too long then backup starts on my local PC an that takes a long time.

I needed this option only once but I cannot unselect that definitif.

My iPad and other iPhone doesn't have this issue.

Both devices make automatic iCloud backup in the night.

Anyone who can help me to undo this automatic local spare backup on my PC?

Best regards, Theo.