Rhinowalk has nice options with a good cost (through 2023 the prices dropped and there are frequent sales too, on the superdeals and similar low prices promotions
I have top tube, handlebar, and saddle bags from them, but all are small - not the bikepacking type. Still, they're well made, and well worth the price. I'm not sure if I'd trust it to last years of frequent and heavy use, though. Like I imagine would be expected from a more known and established brand
used to find Roswheel products too on Ali that have nice quality, I have friends with their bags, but it's been a while since I saw products from them on Aliexpress