Looking for a "custom" script editor

[metulburr]

The reason I can't just continue using the 3D-application to work with python in is that it only works with python 2.7.

Why cant you just point that editor that you have been using to use python3.7? All editors have a method to change which python interpreter you are executing. Some are drop down menus, while others are config files you have to manually change.

What IDE's have you used? Which ones do you feel are clunky?

Have you tried PyCharm?
   

I feel like all the big IDE's would have this feature.

Also every IDE out there allows for custom hotkeys. In pycharm File -> Settings -> KeyMap