Logic Masters Deutschland e.V.

This puzzle is a natural follow-up to Above Average On Average.

I think I am done with this series and I truly think the following puzzle captures the essence of what I was trying to achieve - to make the solver go:

"I have no idea how/why it solves but it just solves."

The difficulty should be more like 3.5/5. Hope you enjoy :)

Rules:

Normal Sudoku rules apply.
Digits must not repeat within a cage and must sum to the number in its top-left corner.
A clue outside the grid gives the sum of digits along the indicated diagonal.
Box borders divide a blue line into segments with an equal sum.

Try it on Sudokupad.

Puzzle: