I've searched and searched for a thread about a softer ride in a Ranger/BT50, the person was having trouble I think it was with the QLD DOT about signing off on changing the seats because the ride was too harsh.
The problem is because the vehicle has the safety pack (side airbags) removing the original seats and replacing them make the vehicle unroadworthy.
I would like a bit of a softer ride myself, I also have the safety pack in my Ranger, so after a bit of a search it appears that Recaro do seats that you can have the side airbag option.
So my project will be to contact Recaro and see if they can supply softer ride seat with side airbags that would be compliant.
It may be worth considering keeping the existing seat, but have it mounted on a suspension seat base.
I just checked, they do exist, but it looks as if it would take a bit of work to remove the existing mounts, and seat base structure to have enough height to fit one.