I had a similar dilemma, but for me it was a concrete basement wall with a painted fabric that was applied in several layers and it stuck like .......
I tried everything from power scrapers, sanders, and finally a diamond grinder (concrete grinder). Nothing worked well

A handheld carpet stripper worked pretty well, but in the end, it was hand tools, chisels, knives, and a lot of hours that solved the problem.
Maybe not a direct answer to your question, but that's how I solved it.