In Islam, a purported belief is disbelief, if the purported believer believes not with full conviction of its definite truth, but as a PLAN B to avoid punishment (if eventually true). So anyone who has a PLAN B belief like the OP is also a disbeliever

As for the Atheists who believe there is no God/ supernatural being responsible for this world & everything in it, and that the world & everything therein Justo occurred by accident.

The analogy for them is simple, you left your home very early in the morning with ur home not arranged. But on returning home, you found out everything well arranged, the home sparkling clean, with ur clothes thoroughly washed, ironed & arranged. Would you say all these just happened on its own by accident without someone responsible. That is the response, how would any sane person allege there's no God in view of the jaw dropping order of this world. The alternating of the day & night, the coming of the rain & the dry season, the various mineral deposits beneath the earth, the death & life of living things, the order order among social insects like ants who live in an organized caste system. Only a full would see all these signs & still believe that there's No supernatural being responsible & That all these things are happening by chance.