Greetings @storiesoferne and architecture+design community users. When I was a teenager I was diagnosed with juvenile scoliosis, from there I was told about postural hygiene practices. What hurts us is a sedentary lifestyle and if the chair can't help us, we have to do it ourselves.

1. We should always keep our back straight.
2. If a lumbar cushion is required, it can be used to help.
3. After 2 hours of sitting, walk around to stretch and move the body. Take the opportunity to go to the bathroom.
4. Have the top line of the monitor at eye level to keep the neck in a comfortable position.
5. Avoid leaning forward to read.
6. Keep legs at 90° relaxed, a little away from the seat to promote blood circulation.
7. At home, try to do physical activities to combat sedentary lifestyles.
8. Practice yoga as a complementary activity.
9. Do stretching exercises daily and include neck and shoulder exercises: Turn the neck 360°, move it carefully to the right and left alternating, then alternating front and back. Subsequently shrink it, as if you were putting your face in your head (laughs), move up and down your shoulders.
10. Sleep with a rolled towel under the neck or an anatomical pillow. Avoid high pillows that dislocate the neck.
11. Control stress, try to be happy...

As a fun fact, I always remember my therapist saying. "I don't agree with chairs with backrests, because in the long run they atrophy the muscles by disuse and when the person gets old he/she will not be able to keep his/her back upright by him/herself". So my advice is to keep your back straight whenever you can. Greetings, have a nice day.