People have killed grizzlys with 357s. A 44mag with the heavier kinds of bullets is more than adequate for anything other than cape buffalo and elephants and rhinos. Bullet weight makes a huge difference.
Grizzlies have probably drowned in pails too — but I wouldn’t want to risk my life betting it would happen at a propitious time and place.
I’ve hunted lots of dangerous game with handguns and don’t know a single serious handgun hunter (and I know, at least casually, most of the serious handgun hunters around - there aren’t that many) that would carry a 44 Magnum for the task. A few carry one as a backup, but most don’t consider it adequate even for that purpose. And, I don’t know of a single competent PH (professional hunter) that would permit a client to use the 44 Magnum for Lion or for Grizzlies. I’m sure there are some, but you won’t find them hunting with me.
You’re entitled to your view, of course, it’s a free country. But please pay up your insurance, so your family will be taken care of, before you go for the grizzly with a .44.