Ice maker woes

I am a retired appliance technician and have come across this issue many times. Since you replaced the inlet water valve I would inspect the flexible supply line for kinks. If no kinks then I suggest a quick water flow test. First if you are using a self-tapping shut-off valve on plastic tubing it could very well be that the cut that the piercing valve makes in the line has closed up enough to slow the water flow. If using 1/4 inch clear plastic line for supply water you can try this test for water flow. With a tall glass and without turning the water off, crimp the supply line to stop flow, remove the line from the inlet valve. Place end of line in glass, release the crimp. If the flow doesn't splash strongly in the glass and comes out slowly your supply is insufficient to close the inlet valve of the refrigerator. Note: These valves are electrically opened and require water pressure to close them tightly. 95% of ice maker water issues I come across are do to improper water flow.