the motor may not like 17V for too long and more CFM will lead to more humidity if you are cooling.
And
While spinning the blades faster increases the potential airflow, the system's ductwork and other components (like filters and coils) offer resistance to that airflow, known as static...
i think on max it may be getting the full voltage. maybe your current fan is not working at 100%, maybe just try to replace it or you wan't more CFM than factory?
Yea, that would be nice, Lincoln use to be a innovator and leader with their cars. An EV to compete with Lucid Air would be nice. But i guess it's all about sales and paying Serena Williams to influence the Navigator.
what is the issue you are trying to solve, it does sound like a blend door issue that is very common.
https://www.lincolnsofdistinction.org/lincolntech/modrepair/blenddoorrepair.html