I'd say she's about toast! What are you growing in? If it's coco, it looks kinda dry. Could be a root issue too! I think at this point I'd pop some fresh seeds.

I’m growing in a peat mix but I’m really trying to save this one because it’s a particularly special seed

Poor thing. I think you killed it.

What’s the mistake so I can learn ?

Felter said:

What’s the mistake so I can learn ?

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Not sure man. The soil looks rather dry in one picture.

Felter said:

What’s the mistake so I can learn ?

Click to expand...

it really could be anything, we don't know much but it looks like she thirsted to death to me kind of, did you ever water to runoff and soak the pot?

If it isn't dead yet, you should set its affairs in order. Plant's deriorating posture suggested increasing osmotic stress, with leaves folding in at first and then top collapse folding. Soil was likely very "hot" to begin with and then improperly watered so that EC kept climbing until it choked the plant out. That's likely how the "botany examiner's office" would describe the plant autopsy. Next go around, pre water your soil before putting a plant in it and make sure there's a good amount of runoff out the bottom, and when you start a new plant make sure you have an adequate volume of water leaving the bottom of the pot with each watering event.

Felter said:

What’s the mistake so I can learn ?

Click to expand...

looks like incorrect watering technique

If that medium is hot i would yank plant out wash roots go hydro until she wakes back up.
My 2 cents i would do

The mistake was probably feeding a plant that already had a root zone/watering problem. In peat, once it gets too dry it can repel water and the water will run channels through the pot, so the root ball stays half dry even though you feel like you watered it. Then the 4-4-4 and that oat/tea nitrogen mix add more activity right around stressed roots. EC climbs, oxygen drops, and the leaves fold up like that.

If you're trying to save it because the seed matters, I'd stop everything except plain water. Slowly re-wet the whole pot once, not a splash at the stem. Room temp water, in stages, until the bag is evenly heavy and you get some runoff, then let it drain hard. No more teas, no more dry amendments, and I wouldn't yank it out and wash the roots into hydro at this stage. That's a lot of extra shock on a plant with almost no reserve left.

Put it under gentler light for a couple days and judge only the top. Dead lowers are gone. If the top perks up and pushes new growth, you still have a shot. If the main stem starts wrinkling or the top dries crispy, she's done.

For next run, pre-moisten the peat before planting, start lighter on amendments, and don't feed a sick plant until the watering pattern is right.