Charging iPad Pro with 87W adapter

Yes, see:

https://9to5mac.com/2022/05/24/fast-charge-iphone-macbook-charger/

Also note that real USB-C chargers are not 5V. They are variable voltage and the output depends upon the connected device's needs.

if it's 5volts dc it is

Watt  is like how fast your car can drive, but the speed limit is how fast your car do drive

the iphone draw as much current as it was build to use when charging, the fact that

a charger can provide a lot more just means it's not having its full capacitive

used