Welcome to the forum @RatsboggleBiological 
Good to have you and a very awesome first thread you made!
Definitely covercrops, combined with a thin layer of woodchips / sawdust
with on top of that a 2 to 5 cm (1 to 2 inch) layer of horse manure and ideally some various mycorrhizal mycelium sprinkled between the woodchips and manure.
Elm oyster mycelium is very tough.
Garden giants are extremely good at retaining water, very thick strands of mycelium.
Alfalfa has stupid deep roots, up to 10 times the height of the plant or something ridiculous like that.
Buckwheat, corn and sunflowers for medium sized deep-ish roots.
Black raddish for big chunky roots, prune half of the leaves when they’re big for mulch and leave them to rot in the ground when they stop growing new leaves.
Brings a big volume of new soil!
And vetch ofcourse!
When they start flowering, chop and drop half of the covercrops and let the other half go to seed so you don’t need to buy any more.
You can already sow your cannabis crop along with all of that and do the same, let half go to seed and return to the soil. Stronger plants every year through natural selection.
And always keep all the covercrops growing along with your cannabis for optimal endless regeneration.
Also create some waves in your soil, bare swales as footpaths in a geometric pattern, for catching water so it doesn’t all drown or wash away during a deluge, and so more water can sink into the soil instead of evaporating.
An acacia tree here and there perhaps, fixes nitrogen and can be pruned twice a year I believe, so it’s all extra mulch and woodchips if you have a chippingmachine, or firewood, or simply wood you can use for anything.
Sowing dandelion (10% calcium) on purpose is good too, makes lots of calcium bioavailable, deep roots too!
Don’t hesitate to ask any further questions here, happy to help!