The anamorphic lens (for projectors at least) really has become obsolete. Lens functionality has become so good with the ability to zoom, shift in all directions and then memorize those positions that it functionally works better than an anamorphic lens, and projectors have enough brightness...
My first attempt at a do-it-yourself 2.35:1 had that very issue. 70mm and IMAX movies were smaller and they shouldn’t be. My next attempt was a 2:1 screen with a bottom black mask attachment that mostly stays in place so that all movies from 1.19:1 to 2.35:1 have the same height and side...