Waterproof case for iPhone 12 Pro

You should be able to find one on google just by searching "iPhone 12 Pro waterproof case". Yous should try and find one with an IP rating if you can (chart) and maybe test it out before hand.

This may void your warranty and you should check if your insurance plans cover water damage, even if you are using a water proof case

I've looked into it:

According to apple (https://support.apple.com/en-gb/HT207043):

iPhone 12, iPhone 12 mini, iPhone 12 Pro and iPhone 12 Pro Max have a rating of IP68 under IEC standard 60529 (maximum depth of six metres up to 30 minutes).

Apple does not make such a case.

No iphone is waterproof.

Apple in no way states they are waterproof.

Correct, iPhones do not have any official ratings

Then you shouldn't say they are waterproof in any way.

Water resistant is not the same thing.