the best thing will be that you ask directly in the Lutris forum
I have not used Lutris, but from what you say, a problem may be that Lutris does not check if you already have the dependency. For example, if a game requires NET 5.0, Lutris tries to install it, even if you already have NET 5.1 installed. That's why the game still works for you if you cancel the NET installation.
But the best thing is that you consult it directly in their forum, which will be more likely to be answered by people who know the program.