I’ve been having similar issues.
In the first set of pics your saddle height looks about right, maybe slightly too low. In the second pics the saddle is way too low.
As suggested above, moving the saddle back on the rails would be a good move for general bike fit. But I don’t think you need a new bike.
Other things that have helped me:
-Peddling from the glutes, i.e. engaging bum muscles when peddling
-Keeping heel down when at the bottom of the pedal stroke
-Specialized Bodyfit footbeds that “fill out” my slightly flat foot.
-Stretching quads.