Awesome! That's an insane value at that price.
I've had nothing but good experiences with AYN's customer support. Sometimes they move a little slowly but you're not going to get screwed or anything, I'd just say be patient. I changed a pre-order like 4 times on a device and they always accommodated.
Once you get this thing in hand, if you want any help feel free to DM me, post here, or whatever. I really enjoy the tinkering with these things. You can use the stock AYN system if you want to just load some games and play, but man you can really "console-ify" your device if you want. Do some searching on Android front-ends. I've personally used Daijisho, ES-DE, and Retrohrai and they all have their pros and cons but really make the game navigation such a cool and sleek experience.
For setup, I'd follow Russ from RetroGameCorp's Retroid Pocket 6 guide, I think that's his latest Android device guide. Setup is 99.9% the same for Retroid and AYN devices, I used that one for my Odin 2 Portal setup not too long ago.
https://retrogamecorps.com/2022/01/16/retroid-pocket-2-starter-guide/