Britannia: Blobz' colourful Sudoku

Today's Video:

Another indexing puzzle right away!

It took a while for this to click for me (as you can see by the video length), but once it comes together, it's an avalanche.

Link to Play:

Britannia by Blobz https://sudokupad.app/blobz/britannia

Rules:

Normal sudoku rules apply.

Digits in row 5 index the position of 5's in their column. Likewise, digits in column 5 index the position of 5's in their row. For example, if r4c5 is a 2, then r4c2 is a 5.

Digits do not repeat along the two marked diagonals.

Digits in cages do not repeat, and sum to the value given.