What you offer is a common argument, but I find it lacking for two reasons.
One is that it only looks at things from a very limited world view and the other reason is that it does not take into account the totality of all that is.
First - the limited world view only sees this - the here and the now - only the visible…it is the view of the agnostic or the atheist. It says - there is suffering and people die horrible deaths. so God, if he exists, must be horrible, or as you suggest above, sadistic. Yet this same God made the earth you stand on, the air you breathe, the food you eat, the body you walk around in, the sun that warms you, the stars that we marvel at, the sunrise that gladdens us and sunsets that explode across the sky in glorious color.
This same God gave us people with heart, and intelligence and good will and conviction who have developed medicines, who have built missions, carried health care to remote areas. He has given us hearts that reach out to our fellow man where he is in crisis with food, medicine, housing, and prayer.
In short - God has shared with us the essence of Himself - Love of our fellow man.
Does this sound like a sadistic God?
Second - the totality of what is extends far beyond this earthly life. We are creatures destined for eternal life. Our lives here, for good or bad will affect that eternal life. Do we embrace Love or not. Do we embrace that which builds up or that which tears down, that which creates or that which destroys. That which hordes or that which sows.
Our faith is not something limited to the narrow confines of this earthly existence. It extends far beyond it. God has invited us to partake of the eternal. Yes our time here is imperfect. Yes there is suffering and yes we will all eventually die - unless Christ returns in our lifetime. But what then? Judgement. God will ask what have we chosen? Life with Him or life without Him. Our life here - good or bad - is how we make that choice.
And it isn’t a choice between this school of deep philosophy or that deep theology - it is a simple choice between love and hate.
Forget the rest - The most important and essential aspect of the life of a Christian - and the most important aspect of evangelization is to live a truly loving life.