I'm not saying it needs to be re-pot due to root binding. What I am saying is,..

It will soon need to be re-potted. BUT, because you want to LST, AND because it's already SO tall and has no lower leaves, AND the lower stem is already to stiff.

Re-pot it now.

However, instead of putting a thick flat layer of soil on the bottom of the new pot, try putting just enough in at an angle to hold the old soil(and the plant) at that angle. then bury it as high up that excess stem as you can fit.

This way, Your main stem turns to roots(being buried). The plant is not so tall(buried). Plus the stem is already angled to the side of the pot(as though you LST'd).

Just be careful to not trap any air in the soil while you re-pot. It'll be tougher to get soil into the area below where you aim that stem, then under a flat re-pot.

After it recovers, start tieing the new growth before it stiffens.

I'd try to find Fox farms soil if you can find it. You'll need nutes soon, no matter what you buy. Organic is best, miracle grow(for example) is known to have some nasty garbage(literally) in it.