In comparing 5e and PF2, it might be helpful to separate non-multiclassing choices and multiclassing choices.
With respect to non-multiclassing choices, I take it that PF2 clearly offers a lot more of these choices.
With respect to multiclassing choices, it's harder to compare the two systems because they treat multiclassing so differently.
As you note, in PF2 you have a main class and then variable degrees of multiclass deviations you can take from your main class. This different approach to multiclassing allows for more variety in some respects, and less variety in others.
PF2 allows more variety in that you can build characters which don't give up any of their core class features to multiclass. So you get a choice between what "angle" you take into multiclassing which doesn't come up in 5e. (E.g., in 5e a Fighter 1/Wizard 19 would look pretty similar to a Wizard 19/Fighter 1, so it doesn't much matter which way you go. In PF2, a Fighter 20 who spent all their class feats on Wizard multiclassing would look
very different from a Wizard 20 who spent all their class feats on Fighter multiclassing.) Likewise, PF2 allows more variety in that it allows you to build characters that can get high level abilities from several classes, which 5e forbids.
PF2 allows less variety in that you'll still keep the core features of your "main" class, no matter how much you multiclass. And PF2 allows less variety in that there are a few "core" class abilities that you can't get (or can't get at full strength) unless that class is your primary class.
So for some maximally dramatic contrasts in what you can/can't build in each of the two systems:
- In 5e, you can build a Fighter 1/Barbarian 1/Monk 1/Rogue 1/Paladin 1/Ranger 1/Bard 1/Cleric 1/Druid 1/Warlock 1/Sorcerer 1/Wizard 1. You can't build anything like this in PF2.
- In PF2, you can build a Wizard 20 who's multiclassed into Cleric and Bard who can cast 10th level Wizard spells, 8th level Cleric spells, and 8th level Bard spells (and not just heightened lower level spells -- spells which only become available at those levels). You can't build anything like this in 5e.