Translation:I am a man, you know.
Or that "I have not washed my clothes for a year", which, to be fair, would be too long.
That's my go-to example when I tell people that I'm learning Japanese.
(Side note: The anime "Choujin Koukousei-tachi wa Isekai demo Yoyuu de Ikinuku you desu!" has a character named Ringo Oohoshi (Ringo being her given name). She'd use that sentence from time to time xD )
I used "I am a boy" on 男です and was marked wrong with the right answer being "I am a guy". Now here, I used "I am a guy, you know" and was marked wrong with the right answer being "I am a man, you know".
I understand that "男の子" and "男の人" mean "Boy" and "Man" respectively, is there a consensus on what word should be used with just the "男" character/word?
Well.. It could either be "he" or "I". If someone assumes that someone is female, then you could reply with " 'she' is a man", where you put emphasis on the 'she' part. Though, if that was the intention, then the sentence would've started with 彼女は. The same would apply to 'it'.
But other than that you're right that there's no indication of subjective in this sentence :)