Thought this was going away, brown spots

My wedding cake auto, straw pie (both 21days old today), and green crack seedling (maybe 10 days) have these brown/yellowish spots on the lower leaves.

The first pics of the wedding cake at first i thought it was drips of nutes on the leaves that just burned them a bit. The plant has been pushing out solid gro and the stems are getting fat! But it seems to be progressing up the plant slowly instead of going away.

The straw pie is a tad behind it in growth and has more crinkle in the leaves and some darker brown spots.

The green crack seedling, not pictured, has the same yellow/orange spots on the bottom set (single finger serrated).

I figured it was calmag possibly but I’ve given some calmag along the way (not every watering or feeding tho). PH is usually 6.2-6.8. Medium is a Coco/Peat mix. Is itthat brown spot disease? Any guesses?

first three pics are the wedding cake with an overtop shot. Last pics are two leaves on the straw pie. My purple punch has zero spots or issues and is competing with the wedding cake for biggest plant. Last pic...

Final note, I’ve been letting the medium get slightly dry(ish) between watering but nothing crazy, the peat holds the water well so deep down it’s still moist in there and def not dry by any means. Maybe PH issues?

Just did a “slurry test” of the soil with distilled (ph’d 7.1) water, about 2in down from the surface in two diff spots. So I’m reading dead on at 6.0 for the top of the soil. I know halfway down and toward the bottom might be different but this would be a general idea.
I added dolomite lime to the medium to begin with but added under the recommended dose because I didn’t want the soil possibly locked at 7.0 the whole grow. I’m also assuming there is enough cal/mag or enough to not have issues, currently in the soil and it’s just not available in the quantity the plant needs because of the lower PH of 6.0.
I’ll be watering and feeding at 6.8ish now to help bring the PH up slowly. While also adding maybe 3-5ml of cal/mag+ just to make sure (I read the coco steals it and the LEDs demand more or some crap lol).

Any opinions on this plan would be much appreciated