Welcome, Senciro09, to Apple Support Communities!
What you have given as the contents of your iPhone 12 Pro Max box is fully complete.
Apple has been completely up-front with the fact that neither earphones nor power adapters would be included.
The cable is a USB-C to Lightning cable.
If none of your power adapters are USB-C, then you can either use any USB (old USB-A) to Lightning cable on one of your power adapters, or obtain a power adapter with a USB-C socket.
Many retail shops, and even convenience stores, sell appropriate cables and even power adapters, these days.
This, and the way so many people already have so many power adapters, is why Apple has chosen to no longer include such common commodities in their iPhone boxes.