I was not able to solve it in time. First tried manually but kept getting a conflict. Have restarted by hand 8 times. Usually number logic puzzles are right up my alley, but for this one the clues always seemed to end up in a conflict with sudoku rules at some point. Resorted to writing a bruteforce program for all combinations for the diagonal, then slowly filter out more and more, which ended up with 2000 combinations at which i couldnt spot a possible answer. Assuming the answer was possibly not in a dictionary but concatenated. By then the deadline was over. Today i wrote another bruteforce program with a dictionary approach, which gave me some plausible answers, with one being the most likely but no way to check anymore if correct. And still out of all those plausible options, none seemed to follow sudoku rules in combination with clues.
See the bruteforce method I described here: Thoughts on Puzzle 30 : Build-Your-Own-Sudoku - #21 by Omer_Mor
It gave very few candidates (~5) and only one plausible (which was the correct answer).
That is exactly what i did when i mentioned my dictionary approach, slightly different syntax of the regex, same output as you described… My issue is that it doesn’t fit with following the clues. And the fact i couldn’t solve it manually. I can only conclude I must be misinterpreting one of the clues.