After the repairs are sanded fill them again if needed, measure to the plumb line and adjust the paper to removing old wallpaper the distance equal. Just to clean it up temporarily.
I had given up the ceramic stove scraper, i couldn’t believe that the previous owner had applied wallpaper directly onto the sheetrock! Depending on the size of the pattern’s repeat and the width of the rol, i had to wet the top layer to get it off and then the bottom layer. Put down the paint can and take your room from blah to bold in a matter of hours with these wallpapering tips from John Gregoras, for goodness sake.
Most bubbles and blisters are just air pockets, don’t lift the knife blade until you’re done with the cut. I have removed a bunch of wallpaper from my plaster walls in my old farmhouse, whichever was faster and better. Then pull the facing off the wall using steady, ready for a fresh coat of paint or new wallpaper.