Those compression readings can't be right. I don't know of any engines that will even fire at 40-70 psi.
One of my lawn tractors has about 60psi of cranking compression. It starts just fine. You need a surprisingly little amount of compression to get an engine to run.
As others have mentioned, check valve timing, that the valves themselves aren't slightly bent, etc.
'18 Ford Raptor, random motorcycles, 1968 Plymouth Fury III - 11.37 @ 118
