If Apple makes a significantly larger touch/drawing device, I don’t think it will be a tablet. If you are going to sacrifice the portability of the design, why be limited by the other constraints of tablets. Some kind of workstation (semi-portable or not) would make more sense. However, I don’t see Apple making something that niche. There would need to be some other major applications, where drawing is only one of the many possible uses.
I have heard a few rumors of larger, much larger, tablets. However, there are rumors like that every year, and I haven't heard of any from the more reliable guess makers.
Who knows. Maybe Apple will shift gears and include touch with the new Apple Silicon laptops when they arrive, with sizes more in line with what you’d like. Rumors on that front are wilder than rumor of new iPads.