Both are used rather often in Polish.
The way I feel it: osoby is about specific people, and with specific numbers , like a party for 24 people, or 5 people died in accident Ludzie is for People in general, sometimes meaning mankind/humanity, also for not specific groups and vague quantifiers
Osoba is a specific person, who did something, or needs something etc. Człowiek is human when you need to say human, and man in the old fashioned way that had man =human, also when referring to oneself, and in "one" construction.
Also often when man is not really about a gender, we say things he is a good man - to dobry człowiek. It is theoretically gender inclusive, but in reality almost always about man.