The Irrationality of Christianity

As I was sick yesterday, I listened to the debate between Archie Polous and Peter Slezak on the subject of “Christianity – is the best fit for the world”. Peter made a comment on x-ans justice being irrational using the example of “if Hitler, who killed millions lives repented before he died, he gets to go to Heaven, and if he (Slezak) and Betrand Russell, who are sceptics about God, died and don’t repent, they would go to hell”. He asked why must he be punished eternally for the sin of scepticsm which is nothing compared to the sin of murdering million lives.
I agree with him that God of the bible is irrational according to human’s rational. God could’ve made human that are incapable of si
ing thus eliminate the neccesity of sending His Son to die to atone for our sins. God could’ve not created Satan in the first place then there’s no one to tempt human. God could’ve used “the scale” justice system, if you do more good work compared to the sin, you could go into heaven.
But at the end of the day, it’s God who chose to reveal himself that way, it’s Him who chose to work in that system. It is Him who chose to sacrifice his own Son for creatures He made, it is very irriational I’d say. Whether we like it or not, our opinion/rational doesn’t really matter, does it? It is not the pot’s place to talk back to the potter.
How can then people who hold high regard to rationality like Mr. Slezak, be saved? Only God can.