Trade in
I wanted to know how much I would get if I traded in my iPhone 11 towards an iPhone 11 pro max?
iPhone 11, iOS 13
Apple GiveBack [formerly: Apple Recycling Program; formerly: Apple Trade-up program] - All computer and mobile devices, including non-Aple brands - "Trade in your eligible device for an Apple Store Gift Card. If it’s not eligible for credit, we’ll recycle it for free. No matter the model or condition…" - https://www.apple.com/shop/trade-in
Also read the FAQ at the end.
You will have to run it through the system to see what they say.