“, I guess I’m an apikores then for asking it”
Yes, by today’s standards apikorsus has been taken to a new level and definition.
You may ask on the Rambam, Rashbah, Tosfos etc but you may not ask on ____ whoever some decide.
You may argue with any Achron you wish (of course with sufficient and over whelming proof,) but not with one termed פוסק הדור.
Personally, if its not a new shailah and there are opinions of prior poskim Achronim disagreeing, i don’t see the issue.
Otherwise, you need to be a fool to think you can just go and argue against someone way above your imagination. Though I doubt it renders one an apikorus – as a shotah is not an apikorus.