Hey mate the marks on your leaves don’t look like bugs to me. Definitely not spidermites like what I had on mine. They leave more of a tiny white spot like the size of a pin head head on your leaves and little mites on the leaves. Worse then the devil!
Kinda looks like something has dried on the leaves in the 1st pic you haven’t Foliar fed your plants or anything have you?
I found with that 1 plant of mine that was yellowing off was a ph issue. Plus the bugs were stressing it out and it was finishing off quicker. Have you checked your ph? And run off ph?