Maybe "a dog" is a little too harsh?

For sure, it's harder to get consistent, repeatable accuracy from these compared to more refined rifles, like many of the models from Weihrauch, Air Arms, Walther and Diana.

I'd certainly do some testing with a wider range of pellets to see which your rifle prefers. You might already be well aware of this, but the difference between group sizes of different (even higher quality) pellets can be alarming at times.

Then it will be down to getting to know it better and how best to manage the recoil and surge. They are lively, but paying extra attention to a consistent, loose hold, trigger technique and follow through, you may well see a large improvement.

Maybe make sure that the barrel detent is adequately lubed for consistent lock up in the meantime.

Check that there is no side to side play in the breech to cylinder jaws area. If there is, take it straight back. If it were a used gun, you could accept this and rectify it, but it wouldn't, in my view, be acceptable on a new gun.

If you have a good relationship with the shop, see if he'll be happy to refund / exchange after this extended testing period.

Hope this helps a little.