So with teh RAK 4631 and a 8db antenna i got 2db better margin on transmit and loads better margin on receive as compared to heltec T096.

Avoid heltec t096.

EDIT: I have found that the FEM (front end module) on the Heltec T096 is finicky. It seems to either cause increased RX noise or outright mutes the receiver. You can issue the command SET RADIO.FEM.RXGAIN OFF to disable it.

Actually the heltec with the FEM disabled seems to have a 4db receiver adavantage over the RAK 4631.