:salam2: brother Sachin4Islam
Allah has chosen Islam as a way of life for humanity. When this messge reaches anyone clearly and they knowingly reject it, then they have rejected the truth as brothers mentioned it earlier.
When Islam comes, there is no third way left, there is either acceptance or rejection because it wants some action and sacrfice, some obligations and responsibilites in order to distinguish between those who are truthful from those who are false.
Have a look at the following few verses (4:141-4:143):
Those who wait [and watch] you. Then if you gain a victory from Allah , they say, "Were we not with you?" But if the disbelievers have a success, they say [to them], "Did we not gain the advantage over you, but we protected you from the believers?" Allah will judge between [all of] you on the Day of Resurrection, and never will Allah give the disbelievers over the believers a way [to overcome them].
Indeed, the hypocrites [think to] deceive Allah , but He is deceiving them. And when they stand for prayer, they stand lazily, showing [themselves to] the people and not remembering Allah except a little,
Wavering between them, [belonging] neither to the believers nor to the disbelievers. And whoever Allah leaves astray - never will you find for him a way.
In fact, it would be hard to say an agnostic is a believer, but instead, it is someone who follows a strong hunch and thus there will be phases of belief and disbelief by giving the other possibility benefit of the doubt also. Therefore, there is wavering in the belief. Surely, an agnostic can never earn the place of a believer, the two are not equal.
Lastly, indeed Allah is the owner of the day of judgement. He forgives whomever He wills.
Hope it helped. Salamu alaikum