2 months and seedlings still tiny

Hi everyone. This is my first year ever starting these seeds and I was wondering if I could get everyone’s advice On where I went wrong.

Here’s some context

Seedlings: S= Alpine strawberry seeds (Started 2 months ago – germinated over 1 month ago) – They germinated really well but then growth stunted and most of them ended up dying – I started hardening them off once I saw the true leaves sprouting – over a 2 week period ( Slowly taking off the moisture done and moving them to full sun) – Seeding mix is coco-pete & vermiculite (1:1:1) – I got stressed and sprinkled a bit of compost around the remaining seedlings earlier today

M = Apple Mint seeds (Started 2 months ago – germinated over 1.5 month ago) – Germinated fast but growth stunted and alot died – Was really green and luscious – Seeding mix ( coco-pete & vermiculite & compost 1:1:1)

The green seedlings are basil plants for reference. (Started 2 months ago – germinated over 1.5 month ago). They had stunted for a bit of time but is finally somewhat growing in the last week.

Watering/ Fertilising – I soaked then I’m water when coco Pete turns brown / is dry – I used a diluted seasol twice on them with 2 weeks in between

Weather – Used to be quite cold with nighttime reaching 1-3C and afternoon around 20C. This week is warmer at nighttime 11C and afternoon 20C-25C – Germinated in outdoor shade in moisture domes. Took them off when seedlings started getting true leaves. Slowly moved them outside to full sun over 1 week. Currently full sun

I’m just looking to see if there’s any wisdom you guys would be able to pass onto me and help me with this issue.