Bro 5w-40 is all you need according to your need .long drive ,motorway continous driving for 5 hours etc what ever the situation and driving condition is 5w-40 is year round good for pakistani climate...
You are using 20w50 which is really outdated...
Prices of liquimoly
5W-40 1290 rs per liter ,4 liter price is 5000
5W-30 is 1050rs per liter
5W-40 is 890 rs per liter
4L can is 3600