Spots

Looks like your soil ph is probs off. If the spots continue to get all over the plant you most likely have your ph to low. You can prob flush the soil with a couple gallons of regular tap water if you tap has ph around 7 to 8.5

Lack of nutrition.She'll be taking the phosphorus and potassium out of the older fan leaves by the looks of it.

to me looks like P/K issue or something weird in the roots like rot. https://420life.com/wp-content/uploads/2021/10/Marijuana-Leaf-Deficiency-Chart-scaled.jpg

Not septoria. More likely potassium or phosphorus problem, either through lack of nutrition or wrong ph. Without detailed diary its hard to tell.

potassium deficiency probably caused by an out of whack ph but it could also be from chorinated water. remember to dechlorinate your