I'd recommend reading "Digital Minimalism" by Cal Newport.

Their writing isn't my cup of tea, but there are good tips in there.

Deleting TikTok is even better for your mental health.

Just make it a rule to hold your phone above your head when using it. Your posture won't be affected, and you will naturally only be able to use it for a few minutes at a time before your arm gets tired. And you won't do it in public for fear of looking like a weirdo.

Thanks for the blog post.