Logic Masters Deutschland e.V.

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This puzzle originally appeared as a six-foot-wide physical display at the first SudokuCon, April 3-6, 2025 in Boston, where it was solved by attendees over the course of almost two full days.

Setters
I constructed the central section, while the grids along the perimeter were contributed by (from left to right):
top row: Math Pesto, Michael Lefkowitz, Tyrgannus, Agent, Scojo, ThePedallingPianist, Playmaker6174, Marty Sears
second row: Qodec, Diane Eaton
third row: Crusader175, Matt Tressel
fourth row: Memeristor, FullDeck and Missing a Few Cards
bottom row: Katie Splendor, Malrog, Florian Wortmann, Timotab, rockratzero, dumediat, zegres, Tallcat
With special thanks to sirxemic, Sven Neumann, Cirne, and Ava DiPietro!

Rules
Normal sudoku rules apply within each 9x9 grid (place the digits 1-9 once in each row, column, and 3x3 box), and all clues are standard as defined below. Cells outside 9x9 grids do not contain digits and are ignored for the purpose of cages and line clues (e.g. adjacent digits on a parity line must have the opposite parity even if there is one or more empty cells between them).
Cages: the sum of the digits inside each cage is equal to the small number in the top left corner (if given), and digits cannot repeat within a cage.
Arrows: the sum of the digits along an arrow is equal to the digit in the connected circle, and these digits can repeat if allowed by other rules.
Thermometers: digits on thermometers increase from the bulb. Region sum lines: box borders divide each blue line into segments with the same sum.
German whispers: along green lines, digits differ from their neighbors by at least 5.
Renban lines: purple lines contain a non-repeating set of consecutive digits in any order.
Entropic lines: along peach lines, every set of three adjacent cells contains one low digit (1-3), one middle digit (4-6), and one high digit (7-9).
Parity lines: along red lines, digits alternate between odd and even.
Quadruple circles: a digit inside a white circle must appear in at least one of the four cells surrounding that circle (if a digit repeats in a circle, it must appear twice).
Digits in cells separated by a V sum to 5.
Digits in cells separated by an X sum to 10.
Digits in cells with a shaded square are even.
Digits in cells with a shaded circle are odd.
Digits in cells separated by a white dot are consecutive.
Digits in cells separated by a black dot have a 1:2 ratio (i.e. one is double the other).

Difficulty
I'm setting the initial difficulty at 5* because of the sheer size of the puzzle, but most of the individual grids should be in the 1* or 2* range (some may border on 3*).