I have no idea, as I don't even know what your bike model is (lack of interest in Chinese bikes on my side, not your fault).
But I strongly believe that most of mishaps after wrenching, are caused by that same wrenching.
What I mean is, an ecu is not all of a sudden broken, just because you set the valves (unless you created a short, but that is an other story)....

So therefore I think you should review your actions, and go over it one by one.
Try to think what could have gone wrong at each step, related to the problem you face now.

I don't think you could have messed up on the valve setting.
However you can check. Normally there is a notch at the end of the crankshaft, indicating the top.
Check again, the operation of the valves is: open-nothing-nothing-closed -open-nothing-nothing-closed-open -->

It however still sounds fuel related to me.
You removed the tank, is there dirt inside?
You might have moved it big time, and that same dirt might now be clocking your filter.
Check that first before anything else.