I've seen cynical takes on unlimited PTO, where in practice nobody took time off for fear of falling behind. Then I've seen organizations that really tried to instill a value around taking time off regularly.
BUT, at the margins, at a relatively non-cynical company I was aware of one person who did their job well, but took more PTO than some vague sense of what was "reasonable" and this person was indeed penalized, despite there being no apparent mark on their performance.
I wonder why there isn't a move to offer a relatively generous PTO packages, say 6 weeks, with the option to receive up to half back as a bonus cash payment if they elected to not take all 6 weeks. That way you establish a sane baseline, but allow people who need R&R to take it without fear of reprisal.