Someone stated that there can be no hell because there is not a single thing they can do that God will not forgive, thus no Hell.
You appear to be making a common linguistic or grammatical error when you state: “that there is not a single thing I can do that God will not forgive.” The problem is your choice of the word “will”.
Our faith is clear that there is no sin God “can” not forgive. However, there are sins God “will” not forgive. How so? In in scripture it states:
Mark 3:29 But whoever blasphemes against the holy Spirit will never have forgiveness, but is guilty of an everlasting sin.”
Luke 12:10 “Everyone who speaks a word against the Son of Man will be forgiven, but the one who blasphemes against the holy Spirit will not be forgiven.”
Matthew 12:32 And whoever speaks a word against the Son of Man will be forgiven; but whoever speaks against the holy Spirit will not be forgiven, either in this age or in the age to come.
Matthew 6: “and forgive us our debts, as we forgive our debtors”. “If you forgive others their transgressions, your heavenly Father will forgive you. But if you do not forgive others, neither will your Father forgive your transgressions.”
In addition, there can be sins we refuse to let God forgive. Or we can have sins we “think” God cannot forgive, which is Idolatry… we are stronger than God. In both cases we do not desire reconciliation. God does not force his forgiveness upon us. The words WILL and CAN are not interchangeable.
Thus it is possible we can remain not forgiven, and so Hell exists.
Countenance of God 