Dutch Flat Mates - Killer Cages: Classic Sudoku Strikes Again!

Today's Puzzle:

Another excellent puzzle from Flinty. A smooth start that cranks up the difficulty quickly and keeps it up!

Link to Play Along:

Dutch Flat Mates - Killer Cages by Flinty https://tinyurl.com/SudokuSleuthDutchFlatCage

Rules:

Normal Sudoku Rules Apply

5's live in Dutch Flats All 5's in the grid must strictly have EITHER; a '1' directly above it AND/OR a '9' directly below it. It may have both, but it doesn't need both.

Killer Cages Digits in cages must sum to the number in the top-left corner, and digits cannot repeat within a cage.