I hope the title is somewhat clear, but if not, here's a picture to leave nothing up to imagination:

From left to right we have:
1. The initial shape, the red line is the stroke, and also the path of the object, while the black area is the fill
-Reshaping the stroke/path will cause the fill to reshape as well, just as would be the case with a rectangle/ellipse/etc
2. The desired result, here manually replicated by turning a stroke into a path, adjusting it, and then adding the "fill" as a separate object behind it
-I want this sort of result, but as 1 object, so that when I adjust the path, that is the outer stroke, the fill automatically follows suit, but 2 separate objects obviously don't work for that
3. What I've gotten with "Power stroke", while I can now adjust the width of the stroke, the fill is applied to the stroke itself, not the object as a whole
4. Same problem, just done with "Pattern Along Path"
-I can also get a similar result by just making a stroke, turning it into a path and shaping it into how 3&4 look, all of which are not what I need
There are 3 solutions I can think of:
1. There's a way to adjust stroke width dynamically while using this stroke of variable width to surround a fill, and I just don't know that way
2. There's a way to link up objects so I'd have 2 objects, one serving as the stroke, the other as the fill, but they behave together as one object
3. A plugin, sort of similar to "Power stroke", that adds separate handles to the stroke for width adjusting, much like the
tool, but without abusing the fill to fill that strokeI hope this is clear enough, and maybe someone has some enlightening words for me.