Needing to exit waste through a joist 4inches below its top face (centre of
joist). Most traps seem to be low profile where the centre of the waste
outlet is as high as possible.

I want to minimise connections and thought it would be great if I can find
a deep (but high capacity) waste trap. Then the pipe can come straight
through the centre of the joist and into the trap with no bends.

Any suggestions?