The revolver isn't a semi-auto and can't be treated as one. It's a wonderful device all things considered. Hunters milk the best accuracy out of it by cocking it first and can take game out to 100 yards. The double action is mostly for defense, when accuracy doesn't tend to be a major factor. With non-magnum shots, it can still be extraordinarily accurate, but spraying magnums is difficult for anyone.
Revolvers point instinctively well and those that have more weight (especially in underlug barrels) tend to do very well indeed when double action firing. You can get good at double action firing, but it can be pretty hard on the K-frame Smiths. I'd recommend a 686 or a Ruger GP-100.
I've mentioned this in other posts, but you also might want to check your chambers by dropping a 125gr JHP bullet into each one. If it falls through and goes plunk!, your throats may be slightly oversized. Wadcutters and other lead bullets tend to be just a tad larger and give slightly better accuracy, but keep in mind that the .357 mag is a powerful round and isn't really conducive to being rapid-shot double action target shooting.
It's sort of like shooting a .44 magnum. A Smith 629 or Ruger Redhawk even in single action mode isn't going to be a tack driver with factory powerhouse loads. They'll bag game at respectable distances, but on paper they don't tend to be very impressive. The .357 125gr JHP has been described as sort of the "perfect storm" of handgun loads. No one really knows why it works as well as it does and even fewer can adequately mitigate the blast and fireball. It's just part of the deal.
When shooting with revolvers, powerhouse loads are just not going to be something you can drop into an X-ring without a lot of practice. It's going to be hard on you and the gun. Just accept it as part of what a revolver is, and what it isn't is a semi-auto. I've seen people dump semi-auto rounds into tight groups in a target, but at 75-100 yards they're just not going to generally do as well as a revolver. The guns are just different.
You can buy a revolver and it will last you a lifetime if it's strong and the loads made for it. The springs won't need replacing and you'll be able to give it to one of your kids. An auto, on the other hand, occasionally needs to have springs changed. Extractor springs, extractors, magazine springs, recoil springs, and so forth. Some change them every 5,000 rounds and it's the price they pay for the technology. You get a Ruger Security-Six, GP-100, 686 or other good revolver and you can check it out in two minutes. Once you check the B/C gap, timing, headspace, cylinder tightness and so forth, you dial it in for your preferred load, clean it, stuff it in a zippered case and forget about it. The more you use it, the nicer it gets.
That's the beauty of revolvers. They're elegant, dependable and they last. If you get a semi-auto, you really need to get it to a range before you can depend on it. If it's used, you probably want to check out all the springs, examine the parts and so forth.
Again, I think you're expecting the revolver to perform like an auto and it just won't do it. It doesn't mean it's bad, it's just different. The 19 is a great gun and isn't intended for a steady diet of full magnum loads. It will pack one hell of a punch, but you can't throw them like you do with a 9mm or .45.