I looked over your grow log and noticed right away that your lighting is not adequate. That 350 watt LED is probably only putting off 175 watts at best. You’ll want to upgrade your lighting to around 50 true watts per sq ft if you want decent growth and yields.
Next your soil and watering. It’s been a while since I’ve grown in soil but I remember my plants liked deep watering a with lots of run off. Let dry inbetween and repeat. Fertigate once per week.
It’s normal for autos to flower after 4 weeks of growth its just usually the plant has grown a lot more.
Now for the soil. Personally, when I grew in soil (I grow in coco now), I preferred a basic soil with no added amendments because I preferred to be in control of all inputs and pH. when you start buying soil with organic amendments, the pH of the soil is altered and then you’re again altering the pH of the water you add. It’s just becomes a lot to manage if you’re new to growing cannabis.
When you watered with plain water, did you also pH appropriately for soil? I always kept mine 6.5-6.8 for both plain water and when I fertigated.