"Now it has lost its luxury of pick and performance. kick would flip. clutch issue etc etc. and give bad smell when parked."
you have mentioned is more related to Clutch plates. Kick slip, low pick, low acceleration, donkey ride when 3 people. If there is no white smoke or unusual sound from the engine then why not just do the repair work for clutch, replaced your clutch and pressure plates, gear box if needed.
IMHO you should not go for the engine overhaul for now.