Logic Masters Deutschland e.V.

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.

Eleven Lines
Each line consists of one or more contiguous groups of cells, each of which sums to 11. These groups of cells cannot overlap. Digits may repeat on lines and even within sums.

Hint to start

Easy leftover maths in Box 8, and the impact on Row 8.
There is a second hint in case you have issues in the mid-solve. There is never a need to case check options.

Hopefully you've done some great work in Boxes 8, 9, and 6 (in that order).
The two stubby lines on the left do invaluable work by Flat Mates, 11-Lines and Sudoku in C3... I KNOW Sudoku in a Sudoku puzzle!?!?!! - lol

Next Week
The lovely Damo_89 makes a welcome return!
You may not even need to take your socks off to do the maths!