... or perhaps learn that frustration presents an opportunity for recognition of areas in one's own education and skills set, from which one can decide to learn more. Something as simple as different bullet weights or powder loads between commercial 9mm ammunition types (there are what, hundreds?) can present too wide a range of impulse energy at the bolt face for any manufacturer to accommodate all of them in one design and setup. A carbine which cycles 115gr +P loads all day might choke up on 147gr subsonics, causing FTE/FTF and quickly becoming frustrating simply because of a given user's ammunition choice. That's not the gun's fault. You wouldn't expect a 50cc scooter to haul a 300lb man up a steep hill, nor a 100ISO film to capture high speed action at night without a flash. Yet so many coming to blowback carbines expect them to function perfectly every time no matter their ammunition choice. Strikes me as representative of ignorance regarding the basics of engineering more than any fault of the manufacturer.
When I bought my TNW ASR, I'd already ordered a length of tungsten rod to put into the buffer weight to slow down cycling, and had a Strike Industries flatwire AR spring in hand before the carbine got to my door as I knew from others' experiences that the supplied roundwire spring would likely cause failures to eject with my preference for 147gr subs. A bit of work boring out the buffer weight and adding a couple of ounces with the tungsten, swapping out the spring, and presto, cycles perfectly every time. Bit more time polishing the trigger and slightly modifying the sear and I had the 3lb crisp trigger I wanted, where the factory trigger had been a mushy mess - but with $840 cost of the carbine being ridiculously cheap for something well designed and machined using high quality materials, I wasn't complaining.
But hey, that's me! I was a machinist long ago, and a bicycle mechanic before that. Been a violinmaker for decades since. As my son says, I can fix just about anything. So tackling firearm functional improvements isn't really difficult, more a fun little side hobby, same as with airgun building before. Not everyone is interested in learning how to make things better. My first girlfriend actually left me primarily because I insisted on improving everything, where she thought store bought stuff was good enough... and, well I didn't think she was quite good enough, with her self-image issues and eating disorder... so yeah, I tried to fix her too. As I did with my wife over 22 years. Failed in both those attempts, as things are easier to fix than people who don't want to get better. So I'll stick to tinkering with my guns and fiddles and whatever. And you just go right ahead and buy something absolutely perfect for you out of the box. And when it breaks, take it to someone who has taken the time to learn, and pay them adequately for their services, and your laziness.