How is sincere repentance (tawbatun nasūḥ) and restitution for injustices (radd al-maẓālim) possible when one is unable to repay them all at once?

Praise be to Allah who has enabled you to repent from this grave sin. However, your repentance will not be complete, and the sin of theft will not be entirely removed, until the rights are returned to their owners. For those you know, return the right to them without informing them of the true situation if you fear harm. As for those you do not know, give charity on their behalf equal to the amount stolen. If you are unable to return the rights, then seek the forgiveness of their owners. If they forgive you, you are absolved; otherwise, it remains a debt upon you. If you die before fulfilling it, and you had a sincere intention to return it, then Allah will fulfill it on your behalf through His grace and generosity.