Don't allow your head/chin to drift forward.

Welcome to "tech neck" - upper crossed syndrome, from looking slightly down.

You're inviting some surprising symptoms, not just neck and back pain, but things like numbness, tingling, or pain shooting down your arms. Really not fun.

Key posture correction seems to be pulling head back. Some physical therapy exercises can help as well.

https://deukspine.com/blog/tech-neck-forward-head-posture-tr...