I think you should mention where you bought it. Mine came pre-assembled without even paying for it from Xpro.
I’m really thankful I didn’t have all of the problems you were mentioning. My valves were always a little bit off. But I rode for 5000 miles before I fixed them. Mine were way too loose
Here is the thread where I did my valve adjustment and there are pics of things you are describing:
https://www.chinariders.net/showthread.php?t=31053
The only thing I had to do with my bike in the first 2000 miles was fix a factory defect for my year were they forgot to put a conduit on the main wiring harness and it chaffed.
Other than that I just put the handlebars on and that was it.
Has been running like a top ever since.
Sorry your place did not put it together well. But you should name it so people know.