for whatever reason my shipping class for all of my variations are stuck on “Same as parent”

You can select any shipping class for the variable product, and also select shipping classes per variation level, but you need to select some value, because by default it uses Same as parent.

Please let me know if it helps.

When they are set up there, you should be able to select them in the variations.

I hope that helps you to figure it out.
Feel free to get back to us if you have further questions.