Logic Masters Deutschland e.V.

Special Thanks
This puzzle was originally set for the immense Scojo imposter setting competition. I had to set an original 'Flinty' puzzle as a benchmark for an imposter to compete with during a live solve, and this is it! It might be easier for some who are familiar with Ten Lines, and aid quick understanding of the rules, if you think of this puzzle as a Ten Lines variant.

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: 2-2.5 / 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.

Seven Lines
Each line consists of one or more contiguous groups of cells, each of which sums to 7. These groups of cells cannot overlap. Digits may repeat on lines and even within sums.

Hint to start

8 and 9 can't appear on seven lines, and don't forget happy 5s, especially in Row 1!

Guest Setter
It is only fitting that next week's guest spot goes to the puzzle that was set to imposter me in the aforementioned prompt, Equal Sum Lines, by frequent guest and friend of the series sujoyku!
I only just managed to defend my identity!