After checking that you can open port 53 udp yourself with, say, nc (which you tried), strace the binary that tries to open port 53 and fails, and find the system call that fails. You can compare it with an strace on nc to see how it differs.

If this doesn’t clue you in (e.g., you see two attempts to listen to the same port…) Next step would be to find in the source code where it fails (look for the error message printout) and start adding diagnostic printouts before the failing system call and compile and run your edited version.

I really wish there were an “adult difficulty” setting to pick instead of ‘easy’. I don’t have hours to waste on hordes of “difficult” enemies that just slows progress and pads the playtime. Nor do I want a walking simulator where the boss just falls over with no need for anything beyond the most basic game mechanics. Give me an option to experience the story with an interesting challenge without wasting my time, dammit!

AND add a clause to the TOS banning retroactive updates of TOS to existing games.