How do disbelievers enter Paradise after embracing Islam, despite the forbidden acts they committed in their lives? Where is God's justice in this, and are they favored over Muslims?

The preference for the end of deeds over their beginnings encompasses everyone, for what matters is the conclusion, whether for the disobedient Muslim if he repents, or for the disbeliever if he embraces Islam, or for the apostate from his religion. This is part of Allah's wisdom in concealing the conclusions of deeds, so that His servants remain between fear and hope; thus, the obedient one does not become complacent, and the disobedient one does not despair.

What has been mentioned is not related to Divine Justice but rather to His Grace. Justice is that a person is not held accountable for the sin of another and that the reward for his deeds is not wasted, which is what the Quranic verses have emphasized, such as: "And no soul earns [anything] except for itself, and no bearer of burdens will bear the burden of another." As for Grace, it is that Allah multiplies the reward for whom He wills without diminishing the reward of others, or that He forgives whom He wills, and this does not contradict justice.