Hey there. First off, I wish my German was half as good as your English. It is not.

Second, you're not the first to suffer from this. The non-English versions often do not get updated or fixed, especially when there are small mechanical changes. This has been going on for as long as I've been playing Inquisitor, and unfortunately, I haven't seen much shift in the approach to localization. So the bad news is that you're probably stuck with some of this.

That said, let me try to help with some of the stuff you're running in to.

1: Loot quality and quality

There are two separate stats. It's possible that there's a localization bug which displays them both as the same. Unfortunately, because you play on PS4, there's almost nothing you can do about this. (Consoles basically prevent you from doing anything useful.) There was a similar bug we found in a beta version a while back, but it got fixed (in the English version) before it was released. It's possible it was never caught in other languages.

I checked the German localization for the PC version (2.3.4), and it looks correct to me:
  <loot_quality>
    <desc>
      <DE>Verbessert die Werte der Verzauberungen und Attribute auf deiner Beute.</DE>
    </desc>
    <DE>Beutequalität-Bonus</DE>
  </loot_quality>
  <loot_quantity>
    <desc>
      <DE>Erhöht die Chance, mehr und seltenere Beute zu erhalten.</DE>
    </desc>
    <DE>Beutequantität-Bonus</DE>
  </loot_quantity>

So the good news is that it will be fixed. But you may have to wait until the console version catches up.

2: Shield on hit

This was also a bug for a while, and it was in the English version, too. Unfortunately, this isn't a localization issue in either language. The actual items got screwed up. Both psalms were accidentally changed to point to the same effect, so they do the same thing. Again, good news is that it's fixed already on PC, so it's just a matter of time before it makes it to consoles. Also, while the effect is a bug, both psalms can still be used for psalm code doctrines without issue.

3: Tarot

This is a bit trickier. The Compendium is meant to serve as a game reference, but there's actually two different versions of the game out there, and they differ in a lot of places. For instance, all of the Tarot cards were reworked in season 2 for PC. The compendium was not updated for that (you can see the updated season 2 tarot cards here). Archeotech shards are the same way: the compendium has them all wrong for the PC version, but they're correct for the console version. However, other things on the compendium *have* been updated for season 2. For instance, the psalm code doctrine changes (e.g., the downside of the triple-shot doctrine being -crit instead of -damage) reflect the current PC version.

Basically, as long as the console and PC versions are out of sync, the compendium is always going to be wrong for at least one of the two platforms.

Finally, while consoles make it really difficult to look under the covers, I will say that the PC version has both localization files available pretty easily. Moreover, I do have archival copies of those localization files going back to the middle of last year. In theory, this should more or less line up with where the console versions are at right now. So if you need something specific compared, I might be able to dig it up for you.

Hope this all helps a bit!