Since you mentioned 4.4mm, thought I would chime in and mention pentaconn (the trade name) which is a TRRRS connection (which does include a ground connection as well as L+/L-/R+/R-. I still do not understand the purpose of the ground connection in these plugs since there's nothing to ground on the other end.

Isn’t it the only common variant of 4.4mm? Since portable balanced audio is audiophile-adjacent, no wonder it includes the common ground of dubious utility.