Have you tried just one TV as close to the antenna as you can get with no amplification? With maybe just 25 ft or so of coax cable? That would give you an initial baseline to start from. (I had to take a TV outside when I installed my system, but it gave me a really good picture of what my antenna was capable of.)
Can you get the antenna higher to clear the trees and buildings in LOS?
Looking at rabbitears.info, it shows KTVD 20.1 on real channel 31, not 19. Which is correct?
Can you do a report on rabbitears and post a link to the report?
https://www.rabbitears.info/searchmap.php
Sometimes moving an antenna up or down or side to side just a couple of feet makes all the difference in the world.