So God is doing us a favour by delaying his judgment, to give us more time to repent, accept Jesus as our saviour, and escape Hell.

Alas, the delay undermines that purpose by contradicting the Christian scriptures, which said the second coming was supposed to happen soon, from the perspective of the early Christians. Thus the delay shows the scriptures are unreliable, which makes widespread conversions to Christians less likely, not more so.

Most of the Christians today weren't converted; they were raised as Christians when they were children, before they had a chance to think for themselves. They were indoctrinated.

The real reason you say God is generous in delaying his second coming is out of desperation, as I said. Like the author of 2 Peter 3:8-9, you're searching for a pious explanation of facts that don't fit your theological narrative. You can do this because your narrative is unfalsifiable.