A big issue often overlooked is the severe muscular atrophy which happens with long duration seating.
The SPINE is naturally supported and maintained by all the surrounding tissue.
With the unnatural arrangement that is seated-life, those supports collapse along with posture, such that even when standing, the spine does not maintain its least energetic shape, further deepening the misalignments and mal-adaptive compressions.
This is not something exercise can fix.
Standing/walking is a complicated, low intensity workout, that the body is DESIGNED to maintain for many hours a day.
Absent that environment, and stimulus to the numerous Dependent-structures, a failure cascade is set in motion.
There is no such thing as an ergonomic chair. There are only slightly milder crippling devices.