Counter point: there are numerous items available fairly early on that dramatically boost ranged AB, and a full sneak attack archer with Mirror Bow is one of the most powerful damage dealing archetypes in the gameI started playing this on the hardest difficulty not being at all familiar with Pathfinder, nor having any idea what I'm doing, and fuck, it's insanely hard. I was already having to use every single spell and special ability just to survive the tutorial. It's possible my build is completely fucked (playing as a Ranger with longbow specialty), but no one in my party can hit jack shit, so battles are a nightmare of RNG (although, I have learned that using the special abilities that increase attack even just slightly can make a massive difference).
I also fucking hate (in fact, loathe), RTWP, which is utter shit because you really have no idea when the masked turns begin or end, and with a game this RNG focused, you kind of need to know that to be successful. I haven't tried turn based mode yet.
Anyhow, I made it to the first village after 2 hours of trial and error. I am very stubborn, love challenges, and always play everything on the hardest difficulty, but ya'll need to let me know if a vanilla Ranger is fine for the hardest difficulty, or if I should restart. My stats are: STR 8, DEX 20, CON 10, INT 12, WIS 16, CHA 8. I took humans for my enemy type perk and the Long Bow specialty perk.
Don't play Unfair if you're not proficient with the systems. In fact, don't play Unfair untill you know the areas, what enemies to expect and what are their weaknesses. Plus know all possible party synergies, party-wide buffing and debuffing options and stacking rules. In short, don't start with Unfair. It really is... Unfair.
You want a big challenge while not being proficient with the systems? You can try Hard. But it will be HARD. DO NOT START ON UNFAIR.
One problem I can see with your ranged build is that you've dumped Strenght. Ranged weapons do use Dexterity to hit stuff - but Composite Bows still use Strenght to increase the damage per shot (non-composite bows don't scale their damage from any stat). So you should have at least about 14 Str at start.
And no, I don't recommend ranged builds for high difficulty settings. They do have the advantage of getting full attacks on enemies most of the time - because they don't need to move to engage the enemies. But their accuracy is sub-par. Most importantly they don't benefit from Flanking. And that is +2 Attack Bonus at base, +4 Attack with Outflank (which all martials should get ASAP) and +6 AB with Outflank and Freebooter's Bond (unlimited use buff from Freebooter Ranger). A 6 point AB gap is really challenging to close. Even moreso on highest difficulty settings, where enemy Armor Class is bloated.