Logic Masters Deutschland e.V.

Deconstruction
Contained within the grid are nine non-overlapping 3x3 square regions, which must be located.
Each region contains the digits 1 to 9 once each, such that no digit repeats in any row or column.
Cells outside regions do not contain digits.

X-Sums
Clues outside the grid give the sum of any digits in the first X cells from the direction of the clue, where X is the first digit in that direction. Cells outside regions have no value.

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.

Special Thanks
Thanks to Palpot for sharing the setting, proposing the constraint, and probably contributing the better clues that really pushed the constraint in cool ways.

This puzzle was inspired by Jesper's Deconstruction: X-Sums
On Monday, I released a smaller puzzle with similar rules that may help: 'Mini Deconstruction X-Sums'

Upcoming Guests

• Series co-anchor Goodcity returns with Kropki's so big they belong in fiction
  
• Then Sujoyku has back to back appearances, first a collab, then a solo puzzle.

To play this weeks Dutch Flat Mates, please click here 'Play CTC'

Alternate link if preferred, please click here 'Easy Mode'.
We have included hidden Killer Cages in 'Easy Mode' to aid with the conflict checker, but it's possible that pencilmarks may reveal regions early. If this link helps even one person with puzzle accessibility then it was worth it.

Optional hint to help with the start:

Regions are placed quite sneakily to make the clues feel almost impossible at first, the 5 clues for example are in different regions. And this is your weekly reminder to think about Flat Mates - haha.

Cross Section Examples:
This demonstrates the X-Sums rule with some optional fills for a hypothetical 12 clue. Also showing that not every row has 9 digits.

Puzzle Image:

I have removed the list of previous puzzles in the series, as I've noticed it is starting to affect the LMD search function. The plan is to eventually list the Dutch Flat Mates on a linked spreadsheet, and ideally edit the older puzzle pages too. For what it's worth, this has been a weekly series since '18 Oct 23' and is the 69th consecutive Wednesday!