Will you stop your espresso earlier if you are making milk drinks ? E.g.Dose is 20g, ratio is 1:2.1, yield is 42g, espresso stops at 42g, latte stops at 38g

Why would you want to do that?

Because I want to make it taste stronger, but am I wrong ?Also, I use light roasted espresso beans

The difference of a few grams of espresso in a latte won't make a big difference in the strength, but it will change the actual taste of the espresso. With everything else being the same, a shorter pull will be less extracted and more towards the sour/tart side which doesn't always pair well with milk. I would either use less milk or put extra espresso in bigger drinks if you want more of your espresso flavor. Good luck!

+1 on CorvusDoug
A good latte or cappa start with a good espresso. If it doesn't taste good as a straight shot, it will likely not be good in your drink.
Thats the difference between brew strength and extraction. 8oz latte and 6 cappa is a good starting point with your double shot.

I wouldn't do that. You would under extract, and remove bitterness from the espresso shot. I am not a big fan of milk drinks, but when I have one, I actually like the bitterness to be there, as it is balanced by the sweetness of the milk, and tastes like milk chocolate.

But how about you try it, and taste it yourself. You might like it.