AFTER you have secured a replacement for your agitator, which I assume is the turquoise one, I would try using a heat gun, moving it slowly and evenly around the base of the agitator column. I learned that these agitators have a plastic spline whereas the Bakelite agitators have a metal spline. In either case, the outside of the spline has a rubber-like compound that holds it in the agitator. With the heat, you are softening this to relax its hold on the inside of the agitator. I don't know if you can warm it enough to allow the agitator to slide up. In every case where we have had to remove an agitator to work on the tranny or other stuff underneath it, the agitator has finally released, but the spline stayed stuck on the shaft and had to be destroyed to be removed. Since your machine is working fine, you are not in a rush to do this.
There is a very nice man on the internet who sells Maytag conventional washer parts. I will see if I can locate his email address if someone here does not provide it so that you can see what he has available for an agitator and what he might suggest for lifting yours.