I have the Haworth Fern chair below and love it. It is expensive, but worth it in my opinion. You don’t want to skimp on something you sit in all day- and I could sit in this chair all day without pain.
My only other piece of advice is to schedule breaks to stand and stretch. I had a standing desk for a while and I did not care for it. I never got used to standing and working- maybe I am just not coordinated enough. But taking standing breaks helped with my back pain and improved my focus.
Good luck!
https://store.haworth.com/products/fern-office-chair?sku=SFTE-U0-7S01A6,4H_FT,MB_SL,TR_7,PM_P
As the other commenter already said, it is really hard to transplant old trees. Think about how big tree roots get. There is no way to save 100% of a planted tree’s roots so cuts have to be made. And by the time you are able to free the tree from the ground, you’ve often cut too much of its roots for it to survive.