2012 M3 Skyactive Repair Help

Tl;dr : it broke. I did work. It's still broke. Need someone smarter than me to point me in a direction.

Hey there friends

I'll try to keep this short but I have a lot here. I got this car about 9ish years ago. (2012 Mazda 3 I touring skyactive) Overall amazing car and has done me incredibly well. I havent had to do really any major repairs to it at all. Just belts/oil/plugs/coils/tires/battery/brake. But overall nothing spectacular. I did add a remote start and android auto about 6 years ago. I wouldn't say I'm any kind of expert with car repair but give me YouTube/reddit/Google I can fix some stuff. I redid the engine on my old Integra once.

About a year ago I had a weird check engine light come up. Cylinder 4 misfire. And it would come and go. Typically show up when it got hot out but then vanish for winter. I was in a really shitty space financially and needed to kick the can down the road for a while. But recently with a plate renewal appearing and my car having died on idle recently I figured I couldn't ignore it anymore. I swapped out the coils and plugs a whole back so that meant this time I needed the fuel injectors based on what I had seen. I went online and was faced with 250$ per injector or 90$ for a set of 4.... I went with the 90$. I bought some gaskets for the intake manifold and had to replace the MAF due to it getting messed with during the repair. Again faced with 200$ or 40$ I went with the 40$.

I turned the car on and it sounded not well. Alot of sputtering and popping. Pitiful idle. I did a reset by unplugging my battery for a bit and then running the car for 20 minutes. The idle got... Better but it's still not ideal. I don't really feel comfy driving it. No check engine light either so I would say I got *something* correct. But the job isn't done yet and I'm at a cross roads.

I guess what I am picking yalls brain for is this. I'm unsure if I should go ahead and repurchase the original parts. Some of my reading said the skyactive is kinda particular with parts and it would want the OEM parts. I am willing to fork out the 1300 to do this however I'll admit I'm kinda scared to do that and end up back in this position. Idk if y'all have any leads on things I can try? Places I can go? (I live in STL and wouldn't mind a shout-out for a mechanic) I'm just at a loss. I have reached the end of my knowledge And am scared this is a money pitt I'm in no position to mess with.

I know that was a lot thank you so much for asking it this far. And thank you for the advice. It's all appreciated.