For the oil change, the biggest issue is nobody in Pk or very few workshops know how to properly change the CVT oil.
Method @haseeb.basharat mentioned is also incorrect. Because you can never find out the correct level of the oil this way.
In the proper way car has to be cooled first, this shouldn't be done on a warm car.
Then CVT oil drained, Refilled, car is started and CVT fluid temperature monitored, along with shifting gears. once it reaches 35-45C then slight overflow is checked at the bottom if it's not there then more more oil is added. Otherwise level's good.
It's a bit complex, but a mostly correct method is here: https://www.pakwheels.com/forums/t/toyota-altis-grande-cvt-fluid-change-transmission-code-k313/995963
Can also YouTube for correct method of Toyota CVT oil change..
But if you can't find anyone who does the correct procedure then the desi method that people use here which basharat brother mentioned can also be done.