Überblüht?

Trichomes getting smaller and changing color to dark brown is only a sign of aging, so is not to worry. But the flower in the first photo looks like having a burn, maybe lamp too close to plant or nutrient burn. If you still fertilize, my advice would be to stop and give the pots a good flush. They look big and mature enough.

I go by the color of the pistils in the first photos, but this could also be due to light exposure and maybe it needs more time.

Photo No. 1 and No. 2 look more mature than photos No. 3 and No. 4 (which are still very immature). I also imagine from the shape of the buds that the first two photos are from some genetics you mentioned; they seem more advanced. But if they have the same time as the others, you'll need to check with a jeweler's loupe and magnification, or use the magnifying mode on the iPhone to see those trichomes better. If the trichomes are milky white or some amber/yellow, you should harvest.

Picture number two has tons of tricomes. Your weed looks fine to me. You really need a jewellers loupe or a little pocket microscope to really look at the tricomes and look for milky white ones. Most of your flower is already developed. It’s not going to magically disappear on you. I think you’re doing well. I wouldn’t stress too much my friend. Enjoy the last bit of flower and have a great harvest. 🤙