The £3m "loss" is not an ongoing situation.
Money was given during Covid as an interest free loan and the club chose to spend some of that money on changes to the park and hunter stand. That is a one time expense. That was not related to any safety certificate. The main stand has had some issues in the past that needed addressing but i believe that is now sorted and not a large on going cost.
So your point about sustainability is completely wide of the mark.