Logic Masters Deutschland e.V.

Japanese Sums Nurikabe Arrows 9x9
The first version of this puzzle was made a few months ago, but I finally got round to refining it today. I believe this puzzle was my longest set so far (~20 hours), and I am overjoyed to share it. You may find this puzzle easier to solve after completing the first one with its ruleset (note that those nurikabe rules are slightly different). If you get stuck, feel free to leave a hidden comment or message me on discord. Your feedback is greatly appreciated, and I hope you enjoy the puzzle :)

Rules
Latin Square: Place the digits 1-9 once in each row and column.
Nurikabe: Shade some cells in the grid such that all shaded cells are orthogonally connected, and no 2x2 area is completely shaded. Unshaded cells form islands, which are referenced by JSS clues. Digits cannot repeat on an island. An island must contain the digit which is its size.
Arrow: Digits on an arrow must sum to the number in the attached circle. Digits may repeat on an arrow where allowed by other rules.
Japanese Sums: Outside the grid, digits may freely repeat and may be higher than 9, but must obey Arrow rules. The values outside the grid give the sum of each contiguous run of unshaded (island) cells in that row or column. Either all or no clues are given for that row or column. “?” is a stand in for any digit 0-9, but for a double digit number, the first digit may not be 0.

The puzzle can also be solved online with Penpa+.