I have been developing a full Dynamo solution for about 6 months and am currently using Python from a String node to connect via VS Code. However, since I have written more than 3,000 lines in some solutions, and sometimes I try different Python nodes to test one function, it would be really great if we had a code editor like experience in the Python node. This would save so much time creating and testing code.
At some point it isn’t the editor, but how you are managing the code. I’d argue your frustration stems from having hit that point and continued to progress. Consider moving some of the code to externally loaded components and then testing parts becomes much more trivial.