there’s actually an easy way on ebay itself. from your seller dashboard you can select all the items you want to edit. then you have to select “bulk edit description” (something like that). there is a find/replace option. then you just type http: into the find box, and https: into the replace box. super easy. also, if you need to remove the old footer, again you can search for the code for the old footer (which is only showing up as the actual footer here for some reason):
and replace with " " (that’s just 1 click of the space bar in the replace box)