Premiere Pro 2022 - masking painfully slow

Hi there

I am hoping someone can help before I pick up my laptop and launch it into the nearest river.

Currently, I've been learning more about Premiere Pro to produce better content. One of the things I've been wanting to do more of is using the masking within the program.

So this morning I'm trying out my first efforts at masking. But PP has gone from working fine with the Proxy files I've created to suddenly slowing down to less than a snail's pace.

I create the mask. Create the keyframe so that I can start animating it. But then when I move to the next keyframe it just grinds to a halt. Why on earth is this?

Is there some way of speeding this up before I head to either DaVinci Resolve or Final Cut Pro and ditch this software and save myself some money each month?

The other issue is when the time indicator does move and I attempt to animate the mask, the bottom part can be moved but the top handle of the mask suddenly adds in a nodal point and starts rounding off the mask leaving me with my head in hands and again wanting to just delete the application.

I'm on a MacBook Pro from Mid-2015 which has 16GB of RAM.

Thank you in advance for any help