What could be the issue here.

1st pic looks like watering splash left under light, 2nd pic looks like where leaves are in contact with ground at night. I'm no expert though! Be lucky

Looks like some tobacco mosaic virus with those lighter stripes in the leaves

Either large PH fluctuations or it is out of range. Hydro and 100%coco range is 5.5-6.5 and soil is 6.0-7.0. If your in 100% coco check the runoff PH and keep watering with 5.8 until you get that number as you cant over water. Soil, Make sure anything you put in is in the correct range. No matter the brand, you must PH. even if they say you don't need to. Its a sales gimmick. Most nutrients will ph for you in large doses, but starting doses are so small you might have to adjust.

some of what i see are just normal blemishes.. the 2nd pic shows something that could be nute related. need more info... without knowing in a resolved way what is in the substrate or what you feed, it's more of a guess than a certainty. no info on substrate or concentration of feed etc... plus, the dosage on any label is esoteric info... this is why kowing ppms is better. you can talk apples to apples that way. are you irrigating every day? except in some specific contexts, you want to have some sot of dry/wet cycle going on. this could be a root isssue, if you are watering every day and it never gets sufficient dryback. if soilless and giving Ca/Mg significantly higher than 100-130ish / 80-100ish ... it's probably lockout.... it could be pH-related if that is unknown. if soil, not only do you have to udnerstand what you have given, you have to have a gist of what was in the soil to start. everything is a relativistic factor... so it is easy to be confused as to a cause of a symtpom if only using a leaf symptom chart as a guide... you'll be right a fair amount of the time, but also occasionally turn it into a dumpster fire. ("crapshoot" that is easily avoided with a modicum of understanding of what was done previously)