There are several threads about OT stands, the idea being in general to align any screen/device with you looking in front of you and not down.
Of course a good combo of height chair/table is important.
There are simple exercises to release tension of shoulders and neck that occur after hours at a desk, very efficient in my case.
Avoiding crossing the legs and having feets on the ground (not under the chair) is also very helpful for maintaining a good posture.
On the hearing side, i try to be careful with the general volume. If i need higher volume for a purpose i try to not have it for a long period of time. Having breaks is a key.
I work with headphones so i chose a DT 880 which is open: closed headphones put way more pressure when working hours in a row.
Edit: for good posture i have a friend who is sculptor on tiny figurines for RPG and he uses a kind of seat pillow that is like a soft ball. It forces you maintaining a straight back.
Also working in sofa/bed is a total killer for the body.