Only the 16-Inch Apple MacBook Pro M1 Max offers “High Power Mode” for Intensive Usage
While it’s possible to spec-out a 14-inch MacBook Pro with the M1 Max chipset, MacRumors is reporting that only the 16-inch MacBook Pro with M1 Max can take advantage of a “High Powe rMode” to be available in macOS Monterey.
So unless you must have the smaller form factor of the 14" model and/or you don’t care about performance (why are you getting the M1 Max?!), it would be foolish to spec-out an M1 Max configuration without going to the 16" model.
There is no meaningful price difference between the two sizes (about $200 5% for a high-spec model), so it is almost entirely about choosing form factor.