Whilst that is true, I believe open sourcing the game would still be better for the current state of whats going on now.
You’re absolutely right, it would make cheating worse. Now that people can read and understand the code of the game (or try to, with all the spaghetti in there.) it will make developing cheats that much easier to do.
Though, I feel it would be just as easy to offset this by putting protections in place that makes it extremely difficult to do so. And the fact of the Orbus community being as close as it is, I think cheating will be much harder to get away with compared to today. I’m more than positive there were players using cheats as far back as the introduction to Reborn. Although, not as many as today. Due to the fact the player count is so much smaller and there are more people open to it now that there’s not really a reason to really hide it anymore.
TL;DR: Open source is better than what we have now, even with its flaws. Though, selling the rights to another dev would ultimately be the best.