by-product vs upshot

by-product and upshot both are nouns.

Word	Noun	Adjective	Verb	Adverb
by-product	Yes	No	No	No
upshot	Yes	No	No	No

As nouns, upshot is a hypernym of by-product; that is, upshot is a word with a broader meaning than by-product:

Other hypernyms of by-product include consequence, effect, event, issue, outcome, result.

by-product (noun)	upshot (noun)
a product made during the manufacture of something else	a phenomenon that follows and is caused by some previous phenomenon
a secondary and sometimes unexpected consequence