Calmag deficiency?

looks like an iron deficiency to me ( just from my minimal experience ) but had a similar issue with a single plant years ago, i scraped rust off a pipe and added it to the topdress and it fixed the issue within about a week, the leaves didnt fix but as they started to die off i just ripped the most deficient ones and pruned the rest as more new growth came in lol i wouldnt suggest scraping rust off a pipe though xD i was old school back then haha good luck! :D

A deficiency of either calcium or magnesium usually presents as spotty markings and with associated chlorosis/yellowing. Personally, I think this is burning caused by an excess of potassium, and not a deficiency of potassium.

Definitely looks like potassium deficiency. https://www.growweedeasy.com/cannabis-plant-problems/potassium-deficiency

It’s a Potassium deficiency . Pretty similar to Calcium deficiency but starts from the edge of the leaves