Hi, just found Endeavour OS and installed the beta. Love it!
1- Will the beta suffice, or should I install the final once it is released.
2- Where do I find Endeavour wallpapers?
endeavour wallpaper, will come when endeavour mature more 
Endeavour is based out of arch you dont need to reinstall.
See here: Logos for Wallpaper art
Welcome to EndeavourOS!
Thank you.