I think you have 2 things going on. Senescence / cold night time temps / genetics can be behind the purple colors -- like "Autumn" colors, if you have that season in your region. It can simply happen or possibly exacerbated by temps at or below 68F. senescence is a fancy word for relating to how things breakdown at the end of life.
The large necrotic damage is nute-related. Looking at the diary it's hard to track how it progressed. More than one thing can cause that damage, so knowing where it started and exactly how it progressed along with a simply leaft symptom chart could help rule out multiple possibilities.
this is the one i use -- duckduckgo image search, should pop up with link, but find a higher resolution image so you can zoom in on each clearly.
https://duckduckgo.com/?q=marijuana+leaf+symptom+jorge&t=ffab&iar=images&iax=images&ia=images&iai=https%3A%2F%2Fwww.coffeeshopseeds.com%2Fwp-content%2Fuploads%2F2020%2F11%2Fmarijuana-deficiency-chart-1024x680.jpeg
when you find one, 'view image' and save it... avoid loading the full web page if from an unfamiliar URL.
ph-lockout or nute-lockout are both possible, too, as hashy mentioned. One is easy to rule out, one takes a more long-term understanding of your fertilization methods to rule the other out. Usually this comes with multiple symptoms that don't make sense compared to a leaf symptom chart, though.