Man United's front line is not a serious problem but it would be better if Man United had to find a new striker considering that Ronaldo is not young anymore and there will always be a possibility that Ronaldo will leave Man United in the next transfer window. 1-0 is not a comfortable victory and we all know that Man United had to work hard to get this win, fortunately, they have De Gea and their defense played pretty well in this match (for Maguire at least he didn't make many fatal mistakes).
I didn't see the game, but according to the statistics, United were just lucky to take 3 points in this game: shots on target 3-5, corners 5-10 in favor of West Ham. I'm glad that De Gea showed himself in all his glory and I hope this will help him regain his confidence. But it is obvious that United should play better both in attack and in defense, more productive (or just lucky) teams with this number of attempts will score at least one goal. It is interesting after the emergency signings that United made against the backdrop of a disastrous start whether the club has any reserves left to operate during the winter transfer window.