So I have two questions, because these are two things which I've realized have been affecting me this past year, so...

1. Basically, I am in the middle of playing, and the main thing is that I kinda start losing focus. Legit, it doesn't matter if it's easy or hard for me, if I feel too stabilized or something (idk what this feeling is), my eyes either drift to the left or right side of the playfield or just drop to the very bottom where my note receptors are. I can't read notes like this, am not focused enough to realize I'm not reading notes, and then miss. It could be sleepiness, but something tells me it's not since I've definitely been more tired before. So anyone know what's up with this?

2. So I started playing in RoBeats where I just learned to hit patterns without missing since I liked how mixed/odd they were, and then started playing osu!mania at the same time as it to become more accurate with hitting patterns. I'd say it translated pretty well, with me getting way more accurate at a slight gain of misses. To clarify, I did try to hit stuff with proper finger/hand form and timing no matter how fast or slow, not just mindlessly spamming.
But right now, I'm pretty uncomfortable with how much I am missing notes, like I'm in a state where I can only try to hit stuff accurately instead of being able to push through slightly-faster patterns. Main question is if I keep trying to play with accuracy, will the misses eventually resolve themselves, or do I need to practice songs/sections with the intention of not missing first and accuracy later? It's not something I'm unfamiliar with, as I have sometimes sacrificed accuracy for survival on songs (basically panic if I see my HP drop a lot), but I'm just unsure if it's something I must relearn or if it's better to not relearn at all.

if you just domt have the focus, then dont bother trying to full combo or SS or whatever. i also have focus issues with easy maps i can actually fc or SS amd like i just fall asleep. for you, try to just get good PA is the way to do good and also MA

getting FCs is not really learnt by accuracy, atleast on 6k, since despite being able to do stuff thats defo 7 stars atleast in map packs my best FC is 4.54 star chordjack iirc and a 1 miss 5.2 star chordjack. i feel like training acc regardless is better though, if you had to pick one then acc is best option

well the amount of hours you sleep could be a good indication.

but, I did have this issue many, many times. Usually it was just my tapping in general, but losing focus was probably the cause of either playing too much, skin problems (notes being too light for example), poor reading. The only way I combat this now, is to either play on HD/FL (usually FL, different way to read), or I swap between skins until I feel comfortable with my main. But swapping from osu! > Etterna, repeat sort of just resolves that.

Speaking of Etterna, you could try to apply HR to your easy plays. Makes you much more engaged, and soon you can play maps you would consider a bit of a challenge to S normally. Random mod does exist too, and it can help with reading as well.

I think imma practice FCing songs then. If anything, practicing that will probably help me focus for longer, and I just like FCing songs (I do have standards for how accurate I should be about it). i liek combo

yeah that is one other thing I wanted to mention.

for warmups, go for PFC (hitting great and above).