do atheists have a back up plan if God exists?

I was always wondering do atheists have a backup plan in the eventuality that the God they don’t believe in actually proves he does exist? This has fascinated me.

In terms of my own beliefs I wouldn’t call myself a nonbeliever nor would I call myself religious or affiliated to any religion or church but I still do believe in God that has a divine plan of sorts for the humanrace which will come to fruition at some stage. In the event it came to fruition do Atheists have a back up plan or if God 100% proves he does exist will atheists still not believe?

I have been doing a lot of research of late and reading books of believers and non believers and visiting various websites so from what I gather the God that Protestents, catholics, Christian groups and Muslims even though it may be a different type of God to them all there is a firm belief that this God has promised that the son he sent into the world 2,000 years ago will return for a second coming to judge the living and the dead. Muslims believe he will return of their faith and from what I gather Christians just believe he will return and don’t seem to specify whether he will be catholic, protestant or a branch of some other Christian belief system.

So, if this God that many believe exists does actually fulfil this promise and this son of his Jesus returns to planet earth to judge the living and the dead obviously if this God fella has the powers to ensure this occurs he would also ensure that when he sends his son back the world would most definately know it was him, whats the point in sending him him back unless he had the 100% untenable proof. Maybe he will have the five stigmata wounds or my guess is he will have the same supernatural powers that he did the first time around which seemed to grab peoples attention so much so they recorded as much as they could in what we now read as gospels or in some cases don’tread. A walking powerful ark of the covenant type of person

So my question for atheists is this, If Jesus returned and had the 100% proof it was him, had supernatural powers, performed miracles,walked on water etc etc and began judging the human race what would the reaction of atheists be? Would there be mass conversions? Would there be sorrow and grief? Would there be laughter? Or would they just ignore it all?

I have a friend who is atheist and when I posed this query to him it kinda spooked him as he had never given it any thought.

Another question I have is how many atheists on this forum were brought up catholic in Ireland and what made you change your belief system? I ask this cause the same friend of mine was brought up catholic and said he was sick of the masses and the prayers his family had to go to and he was sick of the scandals of the church and I was wondering cause if Jesus did return how many people in Ireland that are atheists or non believers or lapsed catholics would blame the church for driving the people away? and what do people think if indeed God proved he existed and sent Jesus back what would Jesus think of the Vatican and catholic church today? although in some ways I admire the church for surviving 2,000 years despite their faults my guess is he would not be a happy camper especially when he discovers the paedophile scandals and that he owns a bank that laundries mafia and drug cartels monies