I would love a whole bagel too. But I learned 30 years ago that I can’t handle a whole bagel, too many carbs! No matter how much insulin I take it seems like it’s never enough.
It does help to put peanut butter, cream cheese, lox, whatever on a half-bagel. I think the cheese/meat/fat help slow down the carb absorption and I can usually dose for that half-bagel without any wild excursions.