I would go for the .357 snubbie.
While you do lose velocity in a short barrel, you lose velocity for
both .38 and .357.
A slowed .357 is still faster than a slowed .38. Don't believe me? Try it. Take a .38 and .357 with the same bullet weight, launch each from a 2" .357 and see which one kicks like the dickens.
Also, there is a fairly good supply of mild .357 ammo out there. So, you can test them until you find one that you can stand the recoil. For example, Winchester USA brand makes a (110 grain?) hollow-point .357 that while giving stout recoil in a snubbie, is less painful than say Federal 130 gr hollow-point .357 mag. Also, MagTech makes a 90gr or 100gr .357 mag hollow-point.
You gotta read labels, though. I came across one light bullet ammo--Corbon maybe--that ramped the velocity up to 1600fps (out of a 4" barrel) yielding over 600 foot-lbs muzzle energy according to the label. Out of a 18-20 oz snub gun, that has
got to hurt the hand holding the gun.
The point is that there is a wide range of loads (and resulting recoil) in .357 Mag, and you can shop and test til you find a milder one you like. Lotsa flexibility there.
And, in a .357 gun, you can also shoot .38spl +P.
Lotsa flexibility to find a load you really like.
Also, if you plan to shoot .357, you might steer toward the all-steel guns. The additional weight helps soak up some of the recoil energy. The ultra-light guns (scandium and titanium alloys) while cool, weigh noticeably less, and are easier to carry. But, are no fun to shoot unless you are a manly man with a high pain threshold.