My iPhone 12 Pro Max already has scratches on the screen even before I have switched it on.

If you’re saying it has scratches immediately out of the box have them exchange it. If you’re saying you use it and scratches showed up during the first day of use...you can still try to exchange it. I personally do not have any scratches on mine or the several others in my family....and this is after going a couple of weeks without a screen protector or case so I can’t relate or say it scratches easy. I could have amazing luck (have had every model since the iPhone 4 and never had scratches) but I don’t think I’m special like that lol). But if it arrived that way I absolutely wouldn’t hesitate to contact wherever I purchased from for an exchange.

Return it for a refund.