If your saddle is too high your hips will rock. Obviously it can't be 10 feet in the air. I rode with too high of a saddle for a couple years due to listening to fit specs. I think foot size also plays a role. Being a size 11 shoe I can ride a lower saddle than someone my same inseam but with size 8 shoe. As long as you can stretch your legs while riding (by pointing your toes up or down every so often) and it feels good, saddle height should be fine.
The OP shouldn't be riding clipless. Since you have brakes just toss some platforms on their with no straps get comfortable riding a bike. You don't sit on the saddle when stopped.
I guess for me mostly when I stop I leave my right foot in the strap, left foot on the ground, but lean the bike. I am probably on the very nose of the saddle since 90% of the time at a stop grab the seat tube to lift the back wheel and set the pedal.
If you are not used to riding fixed, bikes, clipless and sitting so high up in the cockpit - I can see why dismount may be tricky. Just keep practicing.