I've just started my first job with unlimited PTO, and I've never understood complaints like these. I can see how it isn't as amazing as a naive what's-on-the-tin reading would imply, but it seems to me that you can just set your bar at what a normal amount of vacation would be, plus a little bit if you feel like, since they're marketing it as "unlimited PTO". Eg, decide that three weeks is an appropriate, comparable amount, and then take three weeks off.
As I mentioned upthread, I've never had a job where I didn't work when and how much I wanted, go into the office when I felt like it, etc etc. I'm subject to the same pressures you describe, but it turns out they're really easy to handle: keep a rough eye on how many hours you're working.
The other day they had a rare beer release I wanted to go to in the middle of the day, on a Friday. I didn't have any meetings, so I "WFH" and worked 3-4 hours that day and spent the rest of the day drinking and getting dinner with a couple funemployed friends, including checking my email and responding to important ones for a few minutes every couple hours during the workday. I could've (and have in the past) written off those four lost hours of work as coming out of my effective productivity, but since this is a new job and I'm trying to hit the ground running, I just made it up in dribbles of an hour or two over the next week.
The dirty secret when people talk about being pressured at work is that 90% of the time, your employers are relying on you to do the work of pressuring yourself. If my employer wants me to work extra and go above and beyond, I make sure that it's explicit and metaphorically "on the record". Pulling all-nighters during crunch time or forgoing vacation for a long time should be banked as something you can draw on, giving you cover for taking a longer vacation or working shorter days after crunch time.
It's really up to you to set your work life balance, and the fears most people have about the consequences of doing so are largely (but not entirely) illusory.
The one major caveat here that I haven't ever had to face is if you're both at an abusive company and highly replaceable (eg feel like you couldn't get a similar quality job). In this case of effectively having a better job than you'd otherwise get, the power dynamic is markedly shifted and employers can get away with a lot. The only saving grace in this situation is if your more in-demand coworkers have healthy attitudes about work/life balance, since it's hard for management to crack down on individuals in a way that's perceived as unfair.