These are NOUNS:
Walkout, hangout, workout, hangup, setup, startup, kickoff [et cetera].
These are VERBS + ADVERBS:
Walk out, hang out, work out, hang up, set up, start up, kick off [et cetera].
"Breath" is a NOUN and rhymes with "death."
"Breathe" is a VERB and rhymes with Mike Tyson saying "freeze."
These things are not interchangeable. They aren't examples of "either one is fine" or "they both work."
This is some basic elementary school shit and you're awful for screwing it up.
Have a nice day, jerks.