I think the Deck's biggest advantage is what it brings to the table that isn't on the spec sheet. The software it runs is excellent, and thus far Valve has shown great focus on making it the best it can be. The configuration of parts it comes with like its sticks, pads, screen, speakers, and overall design are better than you'll normally get in a Chinese handheld. The ability to actually mod it or repair it in the future is something you'll never get from a more expensive Chinese handheld. Plus you have an American corp. standing behind it.That AOKZOE A1 is really tempting to me given how far off it seems my Deck is. Not that I really need a portable device, but 32GB memory + 2TB nvme drive +1920x1200 screen + a better APU, is quite a big upgrade over the steam deck. Sure it's almost 2x more expensive than the 512 deck in that config, but it just tickles that PC builder part of my brain. I mean it beats my other PC (4c8t i7-3770k intel with a GTX 970) and it fits in my hand lol.
Could you get lucky and get a great handheld that is worth the extra cost over the Steam Deck and be super happy with it? Yes, but it's by no means a given that you'll end up happier with it than you would with a Steam Deck.