Sounds like it could be trigger control, or you're flinching
I think so too.
@MrBitey , your user name & photo strike fear in me. I've lived with a biting cat and it's not cool.
I'm not an instructor, trainer or expert but I can shoot more accurately than any of the people I shoot with, take that for what it's worth...
#1 is trigger control. Everything else can be completely wrong but with good trigger control you will shoot better than most folks. Here are some observations from my perspective:
-Your stance is meaningless , some people shoot sitting down- everyone is different and as long as you're comfortable and recoil isn't making you stagger around like the town drunk , you're fine.
-one eye open VS both eyes open, also meaningless , it helps with your perifreial vision and helps you see more than just your target . many of us (me included) never learned to shoot that way, I still try now and then but it's no good for my accuracy and just feels wrong. I don't care what armchair warrior has an opinion on it, flat out just isn't for me.
-breathing , important but this will directly effect trigger control. You must breathe but don't be trying to hold your breath for 30 seconds to try to get a good group, find a rhythm and use it.
-sight picture, also somewhat important but the catch here us that everyone will take their own sight picture (how you line up the sights). I can grab a gun from a shooter that uses their sights with dead on precision and end up off center, a tight group but off center. Just because I use a different point of aim. Don't seek the group in the center of the target, don't adjust your aim to try to get the impacts to the center . make the tightest group you can, no one cares where on the paper the group is - sights can be adjusted later, just line everything up the exact same way each time.
TRIGGER CONTROL- the most important thing . don't jerk the trigger, don't squeeze the trigger , don't anticipate recoil, don't flinch. PRESS the trigger, let it surprise you (kind of) , continue to press past the break, keep the trigger pressed until you see your impact (or longer if you like) . don't think that you can just line up the sights and pull Willy nilly, it doesn't work like that, dry fire can help you see your muzzle waggle around but it's no substitute for the real deal fire and smoke. Some folks get shaken by the sound or flash, this is the path to a flinch (which it sounds like you have starting) . open your strong hand and relax your fingers, move only your trigger finger and watch your other fingers move too, that's a problem- work on it. Everything can be done perfectly but as soon as you move your hand wrong it's ALL out the window. Learn trigger control and you'll shoot better than 90% of people. The rest gets you the other 10%.
Good luck