Logic Masters Deutschland e.V.

The following puzzle is my special birthday gift (and also a tribute puzzle) to my great friend and also an extraordinary setter grkles. It's also my very first attempt at setting a puzzle with all encrypted clues so certainly I had lots of troubles in the setting process, but in the end I managed to overcome all the difficulty and make a good puzzle out of it.

This one has some pretty tricky deductions at the start but after that the puzzle should flow well again, I hope you enjoy this special edition!
Rules:

- Normal Sudoku rules apply: every row, column and 3x3 box contains digits from 1 to 9 each once.

- A cage (dashed area) inside the grid is killer cage, i.e. digits cannot repeat within a cage and they must sum to the total written in the top left of the cage.

- A clue outside the grid is an X-sum clue, i.e. each clue shows the sum of the first X digits along the corresponding direction of its row/column, where X is the value of the first cell seen from that clue.

LETTERS WARNING!!! Each letter in the grid (B,D,A,Y,G,R,K,L,E,S) contains digit from 0-9 each once, which letter belongs to which digit must be deduced.

- For an X-sum clue, a clue can be single digit or two digits number and in case of two digits number, the first digit may never be 0. A ? is digit from 1-9, which therefore may never be 0.

- For a killer cage, some cages contain single digit that's in the parenthesis and not in parenthesis.
+ In case of number N not being in parenthesis, the cage acts as standard killer cage with total of N.
+ In case of number N being in parenthesis, digits within that cage sum to the total that MUST have digit N as its final digit, and digits CAN even sum to N as a single digit if possible. For example, if a cage contains (4) in the top left, the total of that cage can be 4, 14, 24, etc.

Puzzle:

F-puzzle link

Penpa plus (alt. link)

CTC app (alt. link)

Good luck and have fun solving!