For additional context, these are issues I came across polishing my plugin

That being said, I feel like a TypeProtocol would be rather useful for easier typing when Type or TypeBuilder can be used - though I have not tested this.

These are good improvements! I only saw the following that needed changing:

• The separator to QualifiedName is internally called join
• Need to construct QualifiedName with join from the core struct
• Also need to handle NameSpace type too
• Using Self for types is a Python 3.11 feature, which exceeds our minimum supported Python of 3.9

Given these are all pretty trivial changes, I just added them onto your PR. Thanks for the contribution!