tl;dr: I'm trying to delete and move stuff from an exterior in a conflicting mod and saving it in a "patch.esp" file, but when I load the game, both changes are present. How can I prevent this?

Long Version:

I've been using "Caldera Mansion" as housing since I came back to the game and, while randomly looking for mods to add, I found Carelessly Crazy Caldera Community, which seems to be one of the few mods that add quests to Caldera without changing a lot the exterior.

But oh, it does change the exterior, and right where the Mansion is. So, given 15 years ago I touched a bit the Construction Set, I've embarked on a quest to move stuff around. I checked this page to see how could I create my own patch, and followed these instructions:

1) Load Morrowind (And the expansions) files. 2) Load Caldera Manor (In C:\Games\Morrowind\Data Files) 3) Load Crazy Caldera etc etc (In C:\Games\Morrowind\Data Files) 4) Go to the cell where the changes need to be done, and do the changes: Remove some walls from the base game, add a "wall end" in one spot, move some assets from the mod. 5) Save it as "Whatever Patch.esp"

From here, I move the new esp to my Mod Organizer 2, remove the mods from C:\Games\Morrowind\Data Files\, enable the affected mods in MOO2 in order (Mansion, Crazy, Patch). Load the game, go to Caldera, and while all the walls I moved from the base game are gone and the new "wall end" is there, everything I touched in the mod is duplicated.

My guess is that I've somehow told the Construction set "For this .esp I want these assets here and there" and not "for this .esp I want these assets from this other .esp moved here, here and there", but I haven't been able to find out how to "tell it" that. So, any suggestions on how to make sure the Construction Set understands that I don't want two of each asset touched, but the asset moved?