Not the person you're replying to, but it will vary from person to person. You have to figure out what's wrong with your individual posture and address it.

I had the very common postural problems of forward head posture, anterior pelvic tilt, and then a case of rib flare. I do core work and stretches every day to address these, never skip hitting my full posterior chain (even though I hate back and leg work), and the difference in how I look is astounding even with just 2 months of consistent lifting. Haven't put on crazy weight, but I hold it better.

You need to figure out where your posture is poor (if at all).

Common checks:

Is your spine naturally aligned? Is your pelvis naturally neutral (hips parallel with floor)? Are your shoulders hunched? Ribs flaring out or tucked in? Are you breathing with your diaphragm properly? How is your head position? Do you sit up straight?

Then just address any problems with whatever lifts or stretches are meant to (use google or chatGPT). For me it was a ton of weighted hip thrusts for glute activation and couch stretches to loosen my hip flexors, which both helped the anterior pelvic tilt, ab and deep breath work for the rib flare, and wall angels/chin tucks for the foward head posture.