More years ago than I care to remember, a couple of the ships I worked aboard were taken to Skaramanga for periodic refit and where they were put into a floating dry-dock. Skaramanga at the time was a couple of uncomfortable hours drive northwest of Athens in Greece. Outside of the repair yard there were many privately owned workshops where it was possible to get anything, and I repeat ANYTHING made or repaired.
So long as they had an idea of what it should look like they could copy it, repair it, rebuild it, straighten it out, you name it, no matter what the problem, there was a workshop there that could fix the problem, no problem.
I think the yard was one of those owned, at the time by Mr Onassis and one of his floating toys was in there at the time, all gleaming and spotless.
As you are based in Greece, maybe you could contact one of the workshops in that area and ask the question regarding your rudder, because if they can’t fix it they almost certainly would know someone who could. For sure if my boat was in trouble out there, that would be my prime choice of where to start looking for a solution to the problem.