I keep getting flat tires on my E-bike
You have addressed the pinch flat problem by running higher pressure.

If you are getting repeated punctures, even with new tubes, there is probably something still in the tire that is causing the tiny holes. 

Finding the offending object can be difficult. I was unfortunate enough to pick up a tiny piece of steel wire (possibly a bit of paper staple) in my rear tire recently that just protruded into the tube. I had to carefully inspect both the inside and outside of the tire to find it.