Great job and nice shooting.
First lets talk about the definition of quality because it means different things to different people. The best, simplest definition that captures that meaning is "quality is meeting the customers expectations." Those expectations can be related to convenience, looks, feel, sound, and a myriad of other things.
Cost vs. quality is always a diminishing curve. What that means is with each dollar more you spend you get smaller and smaller incremental improvements. This is exacerbated by the fact you " "expect" better quality when you spend more. When you spend $90,000 on a Porsche 911 you expect it to accelerate faster than a $20,000 Toyota Corolla.
The other thing to remember is everything has a basic function. That 911 isn't going to get you to work any more reliably than that Corolla.
For an airgun that basic function is hitting what you are aiming at. There are some other stuff, like having a quick second shot in case of a repeater but that is a feature and features start adding cost.
So what are some of the things you get when you pay more for an airgun? Here is a short list of some of the things people might pay more for...higher accuracy, trigger effort and crispness, shot count per fill, noise level, finish quality, magazine ease of loading, magazine capacity, ability to shoot at many power levels, ability to shoot many different projectiles, ability to shoot multiple calibers, ease of tuning, accuracy, robustness, weight, size, lower maintenance, reliability, and general looks.
To get to some of the things on that list you get into guns with adjustable two stage triggers, replaceable barrels, externally adjustable regulators and hammer springs.
That can get expensive fast.
Or you can be happy with a less expensive gun that shoots one or a few pellets accurately and reliably, but might need some tuning to reach it's full potential. Heck, for the price of some of the higher dollar guns you could have 4 less expensive guns each tuned for a different power level and/or caliber.
The choice is really yours and it's nice to have choices.
Good luck and again, nice work on that gun and nice shooting.