These type of chairs will take a lot of strain off of your back, as you’re kneeling onto your shins more than sitting on your coccyx all day. Might not be possible to get one in the type of work you do.
https://www.officefurnitureonline.co.uk/office-chairs/kneeler-chairs/kanga-heavy-duty-kneeling-chair.html
Or as beckye recommended, a coccyx cushion will help a lot it you’re sitting in a normal chair. Even an inflatable swimming ring will work really well.
