I think there can be a few limiting factors here...i absolutely agree with the small pot, typically anytime I've given plants a bigger pot theyve outgrown the ones who had the smaller pots. I also think that topping and certain training will definitely slow plants down temporarily. I heard an old timer who's written a few books say that topping isn't necessary, that you can get the same results by tying down....I'm not entirely sure i agree with that, but i can see the lapse in healing time.
Also being week 5, have you started thinking about adding in any sort of "grow" or nitrogen rich fertilizers? Or have you setup the soil with slow releasing products like a living soil? If not i think a plant will usually use up its available nutrients in only a few weeks.
Happy growing ✌️