Logic Masters Deutschland e.V.

Special Thanks
Inspiration for this puzzle comes from The Quaker's Quiver by mathpesto.

Previous Dutch Flat Mate Puzzles
This has been a weekly series since '18 Oct 23'. Here is a spreadsheet link for all the previous puzzles in the series, which also has a few teasers for upcoming constraints/guest setters in the series (subject to change).

This alternative link offers a limited LMD search for Dutch Flat Mates.

To play the puzzle, please click the image:

Initial Setter Difficulty: 2.5-3 / 5

Normal Sudoku rules apply
Place the digits 1-9 so that they do not repeat in any row, column, or 3x3 box.

Dutch Flats
Every 5 in the grid must have a '1' directly above it or a '9' directly below it. It may have both, but it doesn't need both.

Friendly Sums
A digit in a cell with arrows equals the total sum of all digits in "friendly cells" in those directions.
A cell is "friendly" if its digit is equal to the cell's Row, Column, and/or Box number.

Hint to start

It's not really a 'negative constraint', but not busting the sum is crucial throughout the solve, and any time you're stuck this is definitely worth reconsidering. R5C5 is the intended first digit.

Guest Setter
Next week we have another debutant to the series, and you'll have a great time getting all snuggled up with Allagem!