This week, I've seen remarkable improvements following the advice I gathered from the Grow Diaries community. It was definitely a case of nitrogen excess and potassium deficiency. After reducing nitrogen and switching to an organic bloom fertilizer with minimal to no nitrogen content, I've observed significant recovery in my plants. Unfortunately, the combined stress of nitrogen toxicity and a severe heatwave slowed down the growth, and one of the central buds developed mildew. I removed that bud, and now everything seems to be on track. The only exception is one of my autoflowers, which appears to have stressed and matured much faster compared to the others.
You have potassium deficiency and nitrogen toxicity starting. This is usually signs of not enough run off and a salt build up. Which causes havoc on the ph.