Tegmark level IV is the modern version of "Pythagorean mysticism" (it states that "the ultimate nature of reality" is math). So, there is no need to return to anything, we are already there. Well, some of us are, even on this forum. As for "the fundamental nature of reality", there is no indication for it to be a real thing, the deeper we dig, the more we find. But yes, in the map/territory model, math helps build better maps of the territory, whether or not it is the "ultimate" territory. The "weird" parts may or may not be useful in building better maps, it's hard to tell in advance. After all, the (freshly revealed) territory ls also weird.