Hi Bulldawg151,
You're wanting to know if you will be able to activate the iPhones in Germany using a different carrier after you move there. We'd like to do what we can to help.
Looking at the Tech Specs for the iPhone 13 Pro and iPhone 13 mini, it looks like both models can work with multiple cellular technologies.
iPhone 13 Pro - Technical Specifications
iPhone 13 mini - Technical Specifications
To be certain, we'd recommend contacting the carrier in Germany you'll plan to use to verify that each iPhone model you have will be compatible.
Next, you'll want to contact your current US carrier, before you're ready to move, to verify that your iPhones are unlocked, so they can be used with a different carrier.
How to unlock your iPhone for use with a different carrier
Take care.