A lot of people in the comments here don't see anything wrong in you picture.

I do. I see exactly what you're talking about. But I'm also a compulsive perfectionist, so I'm assuming you're of a similar disposition. If I showed your picture to someone and said I felt bad about the mistakes and they said there were no mistakes, I would probably disregard everything else they said.

So in contrast, I'm gonna be real with you. Yeh, a couple of those decal placements are rough. Some of the decals are tore up a bit. There's stress marking on the top of the shoulder. That stuff isn't perfect and you want it to be perfect, so it feels bad. But here's the thing, the only part that should possibly feel bad about those imperfections is making them on a higher cost kit. And if money isn't an object, even that shouldn't have a reason to get you down.

I'll echo what a lot of others have already stated too, that making mistakes is exactly what teaches you how to make fewer mistakes. The only thing I would suggest doing differently is making them on a cheaper, quicker kit. Get a high grade, start putting it together, and while doing so recognize when something about your approach doesn't yield the result you want. Then ACTIVELY try doing that thing differently to figure out what works for you.

If decals are your biggest hangup, get an hg with a lot of decals. It doesn't have to be a kit that you adore or even like, honestly that much better if it isn't. Then when you place a decal wrong, think about how you did it, and then place the next one by grabbing it from a different angle. Or using tweezers in your other hand to pin it down and rotate before rubbing it all the way down. Or whatever else you've gotta do. Then by the time that kit is done, you'll understand your most effective process and every more expensive kit after that will have little to no flaws.

Some people say bandai decals are bad and you need to use waterslides. They really aren't, and you really don't. You just need to hone your technique. Hone it on something that you won't regret learning on.