Well, when you have to play Matic, Mata, Young who has already proven they are useless in the new system, and not only are they ageing but pretty much incapable of doing any pressing then the system is of no purpose. If you consider Pereira and Lingard fighting over who is not the most trash and even the thought of Rashford playing as a lone striker is exhausting. You probably should expect to lose any away game on not being able to play your own game due to these circumstances alone.
Only way to create a playing style is if you have the players for it. If you don't have it, you have to figure out some other way. The thing is, we do not have the depth to get through a season playing only the players we want in the system we want. We do not want to spend any more time on getting the best out of our old and worst players, however we actually have to play them due to lack of depth, which leads to this situation.