I disagree that being someone who fills the “biological reproductive male role” has anything to do with being or needing to feel “manly”.
If you're removing the actual male portion of the word as irrelevant, is your assertion that a woman or enby would use the word "manly" to describe and identity of being a responsible adult?
what it means when a man says “sometimes a man wants to feel like a man”
We're dealing with loose societal definitions, so I'll agree there isn't a single authoritative source. I've shared my definition of what it feels like to be a man, and it largely translates into "handling yourself like an adult, and I happen to be male". The other extreme definition that others may use is likely the most toxic masculinity items you can imagine.
If you're looking for a single authoritative definition of what "feeling like a man" means, you're not going to find it.