I have a peppermint plant in a pot which has been thriving recently after the winter and fertilizer kicked it along well. I suspect I've attracted pests. I will attached photos. There are yellow leaves at the base of the plant and obviously there are holes and silver blotches on some of the leaves at the top. I removed a slug recently but wonder if anyone could give me some insight. There is a microcosm in the soil with tonnes of tiny insects (or something) so it could involve that too.

Sample of top leaves..

Sample of underneath leaves

Attempted photo of mites/insect in soil. There is apparent frass on the dead leaf that is quite prevailent in some leaves now too.

The frass makes me think its a slug or caterpillar but i thought id check for advice.