How to protect a door from dog scratching?

No matter the style of the door kickplates are available to fit or one can be cut down to fit the lower rail. Just measure the lower rail and check the homecenter on what is available or modified.

Maybe try adding a bell to the door so the dog doesn’t have to scratch and can just bump the door?

Hi! Is a doggie door an option?

Go to Lowes or Home Depot and look at the kick plates. Or talk to the people you bought the door from they may have some ideas.

My daughters have both installed a piece of Plexi in a small area on their doors. Then trained the dogs to only signal there.

we installed a clear plexi glass over the door you can get it cut to whatever size you need and we painted the wall/door first then installed the plexi glass piece it is inexpensive and easy to do -

I suggest to use scratch screen. You can buy this ready-made or make them yourself.

This may work for you:

https://www.amazon.com/PETFECT-Scratch-Protector-Interior-Exterior/dp/B075VYW9L5

If you don't mind spending a few dollars on this it might work in this application.

There are driveway alarms that are basically just line of sight motion sensors that alert you when something has broken the line of sight.

These can be used for pets but there intended purpose of alerting you when someone enters your driveway also.

Well, short of training your dog, they make vinyl kickplates for fiberglass doors, take a look here:

http://www.directdoorhardware.com/white_plastic_kickplate.htm

https://www.thekickplatestore.com/vinyl-kick-plates/