Thanks to a wonderful person helping me out, I believe to have figured out the issue. Also thank you to those that contacted me about it!

This has been driving me insane for a while and was partially a case of me not knowing the perfect choice of words to find the answers online.

Not owning Index controllers or knowing anyone close personally with them made it more difficult to test.

I will be updating all of my bases over the week with the fixes!

If you'd like to fix/adjust it yourself in the meantime:

Go to the model fbx and in the inspector under Rig go to Configure

Go to Muscles and Settings

Find the drop down arrows for both the Left FIngers and the Right Fingers

Change each each fingers stretched values to the following