You're spot on, those UA PQP's are really only useful for putting you over the top. You're much better off relying on more direct earnings in most cases.
For comparison, the DL Platinum Amex offers me 10k MQM's per $25k spend, and is stackable, so from CC spend alone you can earn at least one or two elite tiers (setting aside whether that much spend on that CC is good arbitrage across your wallet).