Little Unique Killer Sudoku

Little Unique Killer is an exceptionally thrilling puzzle variant. The puzzle features numbers accompanied by directional arrows outside the grid. These numbers and arrows can appear above, below, to the left, or to the right of the grid. Additionally, the puzzle may include an arrow with a ‘?’ symbol and no accompanying number. Refer to the examples in the image below. The rules for Little Unique Killer are provided beneath the image.

Little Unique Killer rules:

1. Numbers outside the grid indicate the sum of digits in the direction of the corresponding arrow. Digits cannot repeat within a sum.
2. If a '?' appears next to an arrow, it signifies that digits cannot repeat in the direction of the corresponding arrow.

The diagonal digits accompanied by a thumbs up are correct Little Unique Killer arrows, while those with thumbs down are incorrect. It is important to note that in the thumbs-up digits, the sum of the digits matches the number next to the arrow, and there are no repetitions. However, in the left thumbs-down example, the sum of the digits (5, 4, 2, 2) matches the sum next to the arrow, but the digit 2 appears twice. In the right thumbs-down set of digits, the sum of the digits (8 and 3) doesn’t match the sum next to the arrow, which is 10.