وَٱلَّذِينَ كَفَرُوا۟ بِـَٔايَٰتِ ٱللَّهِ وَلِقَآئِهِۦٓ أُو۟لَٰٓئِكَ يَئِسُوا۟ مِن رَّحْمَتِى وَأُو۟لَٰٓئِكَ لَهُمْ عَذَابٌ أَلِيمٌ
Asad Quran Translation
And [thus it is:] they who are bent on denying the truth of God's messages and of their [ultimate] meeting with Him - it is they who abandon all hope of My grace and mercy: and it is they whom grievous suffering awaits [in the life to come].16
Implying that such people deprive themselves of God's grace and mercy (which is the twofold significance of the term rahmah in this context) by rejecting all belief in His existence: in other words, belief in God - or one's readiness to believe in Him - is, in and by itself, already an outcome of His grace and mercy, just as suffering in the hereafter is an outcome of one's being "bent on denying the truth".
Malik Quran Translation
As for those who disbelieve Allah's revelations and deny that they will ever meet Him, they are the ones who shall despair of My mercy and they the ones who shall have a painful punishment.
Yusuf Ali Quran Translation
Those who reject the Signs of Allah and the Meeting with Him (in the Hereafter) it is they who shall despair of My mercy: it is they who will (suffer) a most grievous Penalty. 3443
The emphasis is on "they" (ulaika). It is only the people who ignore or reject Allah's Signs and reject a Hereafter, that will find themselves in despair and suffering. Allah's Mercy is open to all, but if any reject His Mercy, they must suffer.
Mustafa Khattab Quran Translation
As for those who disbelieve in Allah’s signs and the meeting with Him, it is they who will have no hope in His mercy.1
And it is they who will suffer a painful punishment.
lit., My mercy.
Piktal Quran Translation
Those who disbelieve in the revelations of Allah and in (their) Meeting with Him, such have no hope of My mercy. For such there is a painful doom.
Waallatheena kafaroo biayati Allahi waliqaihi olaika yaisoo min rahmatee waolaika lahum AAathabun aleemun