Logic Masters Deutschland e.V.

This puzzle was set for Niverio's portion of the 48-hour-long Twitch train. I decided to lean into the Niverio-classic liar Japanese sums and (hopefully) created something interesting, with a few Easter eggs!

Rules:

Sudoku: Normal sudoku rules apply.
Liar Japanese Sums: Shade some cells in the grid such that clues outside the grid indicate the sums of the continuous blocks of unshaded cells in that row or column. At least one shaded cell must separate the blocks. For every clued row or column, 2 different sets are provided (Left / Right for rows, Top / Bottom for columns.) One set is correct, with correct sums in the correct order. (Always left to right or top to bottom.) The other set is a lie. Which sets are correct must be determined by the solver.
Shading Requirement: No 2x2 region may be fully unshaded. 2x2 regions may be fully shaded.
Notation (1): "..." indicates 0 or more continuous blocks of unshaded cells in the position indicated, with no further information provided.
Notation (2): "?" indicates a one-digit number. Different "?" may have different values.
Notation (3): "??" indicates a two-digit number (no leading 0s allowed).
Notation (4): "?6" indicates a two-digit number ending in 6.

Click the image of the puzzle to play!

Happy solving! Please leave a comment if you enjoyed this one, and check out the Liar Japanese Sums series by Niverio!

Also, there's a hidden message in the grid. Can you find it?