By constructing the sentence
Most Hungarians have a good English accent
I'm trying to say that most Hungarians can speak English well, without a strong accent. Now I understand that 'Most Hungarians' is a plural subject, so should the 'good English accent' agree with the plural subject? However, I'm not trying to say that each of them has their own distinct 'good English accents', I'm trying to say that they have a single English accent that is perceived as good by the general public. That is why I'm inclined to say 'a good English accent'.
Which one is grammatically correct?
Most Hungarians have a good English accent
or
Most Hungarians have good English accents
Another example that is still along the lines of the main question and also keeps me up at night is when I'm trying to say
Those three movies are a masterpiece.
I'm referring to the three movies as three separate movies, but I want to say that in general, they are a masterpiece. Or should I say, 'masterpieces'?
Am I wrong and just forcing a concept from my first language that just simply doesn't exist in English?