Plants grow almost 1 cm per day (3rd week).
Is it too little or correct?
I have the impression that they still lack light (the rods are quite thin and long), maybe I should bring them closer to the LEDs?
They're looking fine a lot of times people are anxious to see results but forget that the plants have their own timeline, you can bring them closer to the light it might make a difference but from what I'm seeing you're right were you should be and with almost 20 years experience I've seen a lot of babies.