I think that even hard difficulty turns early game into bullshit RNG or at least makes it way more tedious than fun. In fact, I don't really know how can somebody make a proper difficulty in pathfinder, the nature of the system is very hit or miss (lol, don't know how to put it better), either stuff connects and whoever gets hit is fucked, or it misses/gets resisted and there's no effect. It is further complemented by two issues.
Firstly, the damage of martial classes is obscene, especially with crit fishing weapons (15-20 threat range) and feats like outflank/seize the moment, add somebody who trips the opponents for even more lolz, and enemies just have very high damage to compensate for the lack of such shenanigans. Secondly, spells are stupid strong, you either save or get killed/completely shut down.
Thanks to this the fights can go 2 ways: your party is able to successfully land their attacks and spells, while somebody with high enough AC and resists soaks every hostile attack and takes no damage (in other words you bypass RNG element) or your party can't crack enemy defenses and tanks don't have enough mitigation and you lose (not enough numbers to bypass RNG). So you know in advance that you either win or lose, there's no reactivity in fights (and that's why they are largely braindead), because that would require significant reduction of RNG involved. And like I've said you either have all or nothing, if enemy is able to land their attacks you're going down, HP and DR do not matter, the damage is just way too high. If enemy is able to land their CC or debuffs you're going down, because of how strong and long the effects are. It works both ways for player's party and hostiles.
In my opinion it would've been better to make the system more deterministic, with more advanced enemies, easier to apply effects, but also much more durable characters and more accessible solutions to various effects (for example, taking damage removes confusion effect). Because now you're either unreacble for enemies and just drown them in damage and CC or they have some stuff in their arsenal that requires very specific things to deal with it (like wild hunt gaze), but shifting it to something like "enemy does A, do either B,C or D to counter" would've been more fun. Of course, that would require a complete revision of the system and getting rid of trash encounters, but a man can dream.