Good evening mr.Archi we cross paths again this evening...haha
I might have an unorthodox idea for your outdoor adventure.... I'm busy using it in my garden right now and it's similiar to a raised bed and fabric pot one...
ms.Amy I hope you don't mind if a share pic with mr.Weedies if that's ok with you....
This girl was in a 50lt bucket and was getting root bound in December, so I dug a knee deep hole and filled with chunks stones for drainage and filled with composted pig/sheep manure, added some bonemeal and kelp powder and mycrohaizal fungi I transplanted her but she was still sticking out half above ground so I sowed 40% shade netting round some wire mesh and because I was scared of direct sunlight on the roots I wrapped it in cardboard which will decompose and the roots will poke through it more than likely one day..... She's just under knee height from the ground to the fork in the branches.....
And here she is today going strong..
Hope that helps you some brother.... You could do the same with your pots, put wire mesh around and cut a hole in the bottom for the roots to go into the whole below but I don't know if you want to sacrifice your bags for that......