I was watching a Japanese animation "Fruits Basket" (2019 version), and the protagonist kept using "ですのに" and "ますのに". I thought it sounded strange. I searched Google with the exact quote and the hit count was a few tens of millions. The first page showed sentences including "ですのに", but since Japanese has no spaces, I am not sure if that hit count is accurate. One grammar page from the Tokyo University of Foreign Studies says
So, if that page is correct, "ですのに"/"ますのに" are wrong. But textbook grammar and current colloquial grammar could be different. I wonder how acceptable they are. Do most people think they are wrong?
Both of them sound natural as far as charactors of fictional works are concerened.
As you may know, some of them speak differently from us for exaggeration, etc.
When it comes to real conversation, we seldom hear them. It sounds too polite or pretending noble, or otherwise joking.