You could try prop_dynamic_ornament instead or use constraints. There is no constraint interface exposed to sp though, you would have to use Phys_constraint or Phys_keepupright:
https://developer.valvesoftware.com/...ys_keepupright
https://developer.valvesoftware.com/...hys_constraint
Or write an extension, see CreateFixedConstraint:
https://github.com/ValveSoftware/sou...cs_interface.h
That way excessive Phys_constraint / Phys_keepupright can be avoided
If you don't care about small lags, you could detach the model from the player and correct the position in playerthink hook. If you set the coordinates and the velocity to be equal to the players every gameframe, it should look like parented entity but without the glow effect