Front squats isolate the quads more - I prefer to do back squats, then isolate smaller groups with quad extensions and hamstring curls; the latter being good for the glutes too.
And I’m trying to find exercises that work in fixing this
Then use postural reminding aids (don't use a brace unless a physio tells you to), I put a small massage ball behind each shoulder blade and the chair when i'm working, if they fall I know i've slouched.
I went from people openly telling me I needed to fix my posture, to being credited with great posture in about 4-6 months. My posture actually still needs work, because I have pretty noticeable anterior pelvic tilt, but the forward-neck issues are mostly gone.
I have anterior pelvic tilt too— what are you doing to correct this?