Lol 5Q (I assumed you meant 5 stars here) isn't unbeatable, but if you face a cup of many 7-9 star teams every single season as I do with my main account, then it is nearly impossible to win the Cup with my 5 star team.
As I said, I am somehow proud of the Cups that I've won without spending real money as other token-buying managers are trying to achieve also. It can be interpreted as the way you said "found a mistake in game engine" to achieve the same result. Ruining the game or not, it's not a big deal to me because I've already experienced losing to power-trained, token-buying higher-level teams so many times already.
If I am ruining the game, then power-trained, token-buying teams are also ruining the game because both have the same implications that we all want a team that dominates our opponents by either exploiting the game loopholes or spending real money , creating an inherently unfair game. So for me I don't see any difference.
The only way Nordeus can fix it and make it fair is to eliminate all the buying features with real money except for club kits and logo, and put all teams with the same level in all 3 competitions.
Well, I will stop here no more post in this thread simply because you possess a very strong sense of justice and fairness in this game which I unfortunately do not have and so cannot share with you. Sorry for ruining the game, but just being optimistic, token-buying power-training managers and I (in this sub-account) are just creating a more challenging game for weaker teams as I am also experiencing myself in my main account.