I used keybr to learn to touch type. I have an office chair with a head support to reduce strain. But I often found I was hunching forward after a short time at the keyboard. I realised I was moving into that hunched position so I could keep glancing at the keyboard as I typed. It’s taken a little time but now I can touch-type, with my head and neck relaxed and my posture is much improved.
My progress was slow because I have chronic pain in my hands. When I started typing I would get pain very quickly. I kept practising frequently but only for a minute or two at the beginning. By staying just within my pain threshold and practising regularly I have been able to increase my stamina and decrease my sensitivity.