The thing is, why do mathematical objects need to be ontologically real? The way I see it is that mathematical objects like numbers or algorythms in scientific theories are descriptions of the physical world a bit like words.Why would we think that words actually onthologically exists because they accurately describe objects?
If mathematical objects were ontologically real, how would that work? For example take a triangle. Say there is an abstract triangle that ontologically exists as an abstract object. In what sense is that a triangle? It is only the concept. If the concept was indeed a triangle itself, it would be a particular and not an ideal. If it is not itself a triangle, how can it be the form of a triangle?
For example, when we say sherlock holmes exists, we are talking about Sherlock Holme's properties as encoded information--it's not lke we literally believe there is a detective from England existing that we could go and touch.