Sounds like the solution for you is wearing the bass low but at a high angle, this is ergonomically helpful in several ways.
However 99% of basses are neck-heavy even when horizontal, and rapidly become more so as playing angle increases, due to overall design and strap button geometry. Playing at a very high angle is difficult and also somewhat uncomfortable as the strap pulls forward hard over your shoulder.
A T-Bird is very unergonomic and very poorly balanced due to having no top horn, this also shifts the bass to the left which is bad for the fretting arm. I'm surprised you found a Jazz bass (Fender copy i assume) worse, as those at least have a long top horn.
For high angle playing a headless bass will help a lot.
Sadowsky NYCs and G&L L2000s are not remotely ergonomic, neither are ESP B series basses, all of these are basically the same Fender P/J type design which is inherently unergonomic.
99% of basses have bad ergonomics because they are recycling designs from the 1950s-1970s, because 'rock band fashion' dictates most bass design.
Ergonomics requires a radically different design, and probably headless.
