That's...a fairly low annual PTO for a senior level person in a place with quantified PTO, so if that’s your “reasonable limit” in an unlimited PTO environment, it seems to confirm the “unlimited PTO means less PTO” suggestion.

Yea 20 days is great for jr level but if you're with the firm for more than 5 years or above manager level it's kinda low for how many days you'd get (and thus be compensated for if you leave)