This is not my experience, having worked at "unlimited PTO" companies for my entire career. You end up with people on the team able to take radically different

This is not my experience, having worked at "unlimited PTO" companies for my entire career. You end up with people on the team able to take radically different amounts of vacation depending on the current projects, who is engaged in the mission critical stuff, etc. The absolute worst position to be in is on a critical but non-visible infrastructure piece, where nobody outside the immediate team notices your impact, until it falls over and takes the entire business with it while it's offline. You end up without flashy deliveries to leverage as political capital to advocate for yourself, yet still with the downsides of having difficulty justifying time away due to business risk.