“How about just looking at any site that lists handgun ammo with both speed and weight of the bullet!”
Feel free. The Buffalo Bore 44 special is a 255 grain bullet moving at 1000 fps with 566 ft/lbs of energy.
Federal Premium Personal Defense ammo in .357 pushes a 158 grain bullet at 1240 for 539 ft/lbs.
I prefer the former. You are welcome to choose the latter - I regularly load my Model 60 with Buffalo Bore’s .38+p: a 158 grain bullet moving at 1000 fps with 351 ft/lbs of energy.
BTW - I don’t believe energy is an accurate prediction of ‘stopping power’, but it is a widely available tool for comparing in a general sort of way. I think any of the loads I listed will do about as well as any load can do against humans.
I carry full power 44 mag loads for fun - trying to save some money using Prvi Partizan moving a 300 grain bullet at 1280 fps with 1095 ft/lbs. I think that is a bit too much for self-defense against humans...but it makes a big boom coming out of a 2.5 inch barrel. What’s not to like?