"Have you ever even used either product??? That statement is just ludicrous. " Gardz was formulated to seal torn drywall, Kilz will not even come close to the performance of Gardz, not even on the same planet, get real." I have tried both of them. "Formulated" is in the eye of the manufacturer and the advertising department. I could care less about what the sales garbage says. "Latex Kilz product are highly marketed, over rated primers. If you were a professional painter and did this for a living you would know this. " I actually prefer shellac to avoid adding ANY water to the damaged surface, guess you missed that. The only reason to put anything on damaged drywall before repairing the surface is to reduce the movement of water from joint compound into the damaged cardboard causing any further swelling. Setting compound does a lot better than premix. You can use only as much water as you need to get a mix for skimming. Failing to remove left over paste before finishing is just foolish, and is not the issue here. Any coating is not being used as a primer to improve adhesion of the paint, just to block some moisture. Just about any primer will work for this, and it is going to get buried under a layer of drywall mud when the area is skimmed. Anyone who knows how to reportage damaged drywall and skim coat would know this. The painters do NOT know (ever watched them try to fix plaster?). They paint things, not install and repair walls.

The description of that home improvement show episode rang a bell for me. But I thought that the solution they actually used was to put up new dry wall boards, and cover up the old crappy walls. (And then taped the new seams, skim coated the seams, sanded, etc). I don't know if that is a viable option for this room in your house. Adding new boards messes up the spacings for existing trim. The reason why it worked for the TV episode was they didn't seem to have any baseboards to start with, and part of the episode was choosing new trim that they'd be adding after adding the new dry wall. I agree about saturation (lots of hot water) being the key to removing wallpaper. Did you use a steamer when you removed wallpaper previously? My dad used a steamer to remove wallpaper in our childhood bedrooms, and he still recommends it.

Does R o S really have to come inside for the winter in your climate? I don’t quite understand about the watering. Do you use the globes for all watering? Even when you’re not away? A picture of the flakes would help people id them. But since R o S is deciduous anything on the leaves will go when the leaves fall.

Change out the fluorescent bulbs to LED bulbs in your fixtures. They make the same shape bulbs in LED so you can improve the quality of lighting in your room. I would consider a peel and stick removable wallpaper to aid in installation and removal in case you get tired of it. This pattern is fresh and clean and available at Lowes. https://www.lowes.com/pd/NuWallpaper-NuWallpaper-30-75-sq-ft-Multiple-colors-finishes-Vinyl-Abstract-Self-Adhesive-Peel-and-Stick-Wallpaper/1001154080