Don’t doubt the dipstick, the oil level was low. The oil consumption may be due to stuck oil rings on the pistons, the cost of repair will be greater than the cost of a newer car.
I think 5W20 is the recommended oil. For my 1999 Civic EX, the original rec was 5W30 but years ago they changed it to 5W20, which I have used since learning of the change.
Using the wrong oil can mess up the variable valve timing - as the owners manual and others here have been saying.