You’re right to be wary of unlimited. It’s primarily a way for employers to avoid having to pay out accrued vacation time when staff leave. And create the competitive environment you mentioned over taking few days vs a lot. It seems great at first glance but I’d prefer a set number of days, no ambiguity that way.
I’d also like to hear more about it. I’m not sure I’ll stick with proton after my sub next expires and infomaniak seems a strong competitor