TL;DR. Two $0 cards optimized very differently. Wells Fargo Autograph earns 3x on six broad categories (restaurants, travel, gas, transit, streaming, phone plans). Freedom Unlimited earns 1.5x everywhere plus 3x dining, 3x drugstores, and 5x Chase Travel. Autograph wins on raw earn breadth at the higher 3x rate. Freedom Unlimited wins when paired with a Sapphire because the points become transferable.
The three dimensions that actually decide it. First, category breadth. Autograph's 3x covers six categories with no caps, which is the widest 3x net on any no-fee card. Freedom Unlimited's bonus is narrower (dining, drugstores, Chase Travel). Second, transferability. Freedom Unlimited points combine with a Sapphire to unlock Hyatt and United transfers. Autograph points combine with the Autograph Journey for Wells Fargo's transfer partner list (no Hyatt, no United). Third, no-fee standalone value. Autograph stands on its own; Freedom Unlimited's full value depends on a Sapphire pairing.
Real customer scenario for each. If you do not have or want a $95+ companion card and you want maximum earn from a single $0 card, Autograph's 3x on six categories is the best in class. If instead you already have a Sapphire and want a $0 card to fill non-bonus spend with transferable points, Freedom Unlimited is correct.
The trap to avoid. Picking Autograph because of the 3x and ignoring that Wells Fargo's transfer partner list excludes the U.S. carriers most people redeem with. Autograph's points are great as cash equivalents; they are not great as transfer currency.