In Islam, disbelief in God is a major sin, as stated in the Quran where it says, "Those who disbelieve in Allah and His messengers and seek to make distinction between Allah and His messengers and say: 'We believe in some and reject others, and seek to take a way in between' -- these indeed are disbelievers, truly" (4:150-151).🏵️🏵️

Blasphemy is also a serious offense in Islam, as stated in the Quran, "Those who insult Allah and His Messenger, Allah has cursed them in this world and the Hereafter and prepared for them a humiliating punishment" (33:57).

However, it is essential to recognize Islam's emphasis on compassion and respect for all individuals, regardless of their beliefs.
Prophet Muhammad (peace be upon him) taught, "Those who are merciful will be shown mercy by the Most Merciful. Be merciful to those on the earth, and the One in the heavens will have mercy upon you" (Tirmidhi).

Islam also places great importance on the principle of freedom of conscience, and stresses that faith must be the result of personal conviction and not coercion or force.
As mentioned in the Quran, "Let there be no compulsion in religion. Truth stands out clear from error" (2:256).

Pharaoh - as an example - denied the existence of God Almighty, and Moses, peace be upon him, was sent to him urging him to repent and believe in God alone.
The Qur’an mentioned these atheists and called them to repent, as was the case in the story of Moses, peace be upon him.

Therefore, the story of Moses with Pharaoh was repeated in the Qur’an, since he was more stubborn and more infidel, unlike the rest of the infidels to whom the other messengers were sent.
Most of them were steadfast in the Lord Almighty, acknowledging that He is the Creator of this world.
They were on opposite sides of the world.
Truth and falsehood, for Pharaoh was in the utmost disbelief and falsehood, as he disbelieved in divinity and the message, and Moses was in the utmost truth and faith in the sense that God spoke to him verbally, and God did not place between Him and Moses an intermediary, so he established the perfection of the message and the perfection of speech, and confirmed the Lord of the worlds with the attributes he deserved, and this is in contrast to most of the prophets are with the infidels, for the majority of the infidels do not deny the existence of God, and the messengers also did not have the ability to speak as Moses did, so the story of Moses and Pharaoh became the greatest of stories and the greatest of consideration for the people of faith and the people of disbelief.

Every infidel, polytheist, or atheist, regardless of his polytheism, disbelief, or atheism, if he turns to God in repentance and repentance, then God accepts his repentance, removes his stumble, and forgives his sin, whether it is a human or a jinn.
As the jinn are charged like humans, they have been called on to believe in Muhammad, may God bless him and grant him peace, and to follow him, which indicates that this will benefit them if they repent and return to God Almighty.

It is true that some Muslim-majority countries have laws that criminalize atheism or punish blasphemy severely. However, these laws do not necessarily reflect Islamic teachings or values, but rather local cultural, political, and social factors.

Moreover, Islamic ethics teach the importance of moral virtues such as justice, compassion, mercy, and forgiveness, which are considered essential for the individual's spiritual growth and the well-being of society.
The Prophet Muhammad (peace be upon him) once said, "The most merciful of people to people are those who show mercy. Be merciful to those on the earth, and the One above the heavens will have mercy upon you" (Abu Dawud).
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Before I go, I want to know, what are your reasons for not believing in a higher power or deity?🛑

I suggest that you read some articles exploring why some people do not believe in the existence of a higher power or deity, as well as my responses to their arguments. It might be informative and helpful in understanding different perspectives on the matter.
https://medium.com/@mohamed-phd/list/00bd1f514dcd