There is something in the equation that needs to be eliminated, I have rooted some sorry lookin stuff from my trim trash just to see if I could. The greenhouse domes that hold humidity, 800 ppm well water? My final method is an oxycloner and Clonex solution, cutting 45 degrees through a node, dipping in rioting powder, snipping through the fan leaves, a 30 watt led shop light on 18/6. You seem to be over thinkin this I have never had a failure. Your descriptions of your failures all seem due to excessive humidity which they do not need to root. Keep it simple I have just plopped em in a glass of water and waited a couple weeks, no covers or spraying they are not tropical plants. Invest in an oxycloner and proper solution, your method seems to be correct untill you rot your cuttings with excessive humidity. It is so simple I feel like you only need to tweak a couple of things, loose the cubes and all that you don’t need em they may be part of your issue. Get an oxycloner and be done with it, leave the leaves so the cuttings can feed on them while they get their roots goin they will yellow and dry and thats a good sign they are comin to life
View attachment 1150440