“a Ruger Redhawk .44 mag.”
Or a Smith 629 mountain gun.
https://www.budsgunshop.com/catalog/product_info.php/manufacturers_id/31/products_id/26324
But you have to have very strong hands and wrists to be any good with it. 4in barrels have a lot of snap.
I prefer the Smith 586 4inch. It stops all except grizzlies.
With any luck and a good load, .357 would stop a Grizzly too.
I saw an article here of FR which listed Grizzlies and Brown Bears in Alaska which had been killed with handguns.
I was surprised by how many were 9mm. Not that I would recommend it. Still it would probably do OK against a Cougar.
How about an 1858 Remington .44 caliber revolver—or better yet, a Hoodah gun. Double barrelled action and full of shotgun in a pistol fun. Developed to fend off the tigers that climbed up the side of an elephant to attack the riders. Yikes!
I will be fully retiring soon to my old family home in northern Michigan. I now carry my Smith Model 29, 6" barrel, whenever I go out onto our property in the woods. There are many black bear and now confirmed cougars.
All the way through the 80s I could just go out there to shoot, hunt, or cut firewood without having to worry about getting attacked by predators.