RPGMemes

Sorry for the delayed answer. In short, there's 17 separate classes that don't have that problem out of 29. So partially free, can be done though.

It’s still mostly a spells-per-day game, right? You probably don’t lose the first fight of the day because you can go nova

Spellcasters have limited spellslots, yes. Pathfinder 2e even still has some Vancian spellcasting in a few classes, but there's enough classes that you can still have your pick of spellcaster without that restriction if you hate it (and an option to make any Vancian spellcaster into a non-Vancian one too).

Spellcasters are only 12 out of 29 classes though, and with some exceptions (Alchemist) all martial classes are ressourceless (well, outside health haha), or have some "per-fight" consumables (called Focus Points for spells, other classes can have their own specific versions) which they can get back during a 10-minute rest after a fight. Which tend to happen anyway, as healing is also done in 10-minute increments and PF2e is mostly balanced on starting fights while healed.

It’s been really interesting playing Vampire with a person who’s only ever played DND.

Then again, even in DnD resourceless classes exists, so they may have played spellcasters only (which is understandable, since they tend to be more powerful and interesting in most editions). There's always a learning curve for other systems though, especially going from their first to second system! I remember going from D&D3.5 to Call of Cthulhu being quite a culture shock haha. And then trying out Shadowrun...