Wow, really good answers here, thanks!
I think I got bad posture because I trained the wrong way. First, too much pressing going on, then when I tried to fix it by training back, maybe I wasn't contracting my scapula the right way. I was just squeezing them together and didn't think about pushing them down as well. Not sure if this had an effect though.
But maybe my biggest mistake was that when I was doing the one arm bent over row, I rowed it to my chest instead of my stomach, which probably created a huge imbalance between my upper and lower back (strong upper lats, weak lower lats)? I was doing it cause I thought hitting more of the rear delts would help pull back my shoulders lol.
My core and glute is pretty strong and I am doing dead bugs to strenghten my extremely weak hip flexors caused by APT.
I'm also doing mobility drills every day but I still feel doing the correct exercises will solve this problem a lot quicker. At least it's getting better and better so will just have to keep going! Resistance bands are on their way so can't wait to start with them! Once my shoulders get better, maybe it will all improve.
Now, I just need to learn how to deadlift
Hope it won't be a problem with weak hips