The four options are these. And one of these four must be what happens

Present terms

New terms

No terms

No Brexit

Present terms: Single market and customs indefinitely. This is so colossal a policy failure that Johnson is forced to resign.
The government collapsed and the party split, with no viable policy, the Tories will be forced into another election

New terms: Europe will only offer May's deal, which Johnson rejected. If he tried to pick that up now, his party would mutiny. He would be politically finished.

No terms: Well, that can only happen if parliament agrees to it because labour will bring a vote of no confidence before the end of the year.
And Johnson will lose that vote because by then the Tories will be desperate to get rid of him

No Brexit: Or at least, single market and customs. Which we can do, but Johnson himself cannot.
Johnson has so postured himself about all the Brexit things he's going to do, that he'll be forced to resign.

And that's all the options there are. Present terms, no terms, new terms, no Brexit.
Johnson has to choose one of those four, and every one of them will see him resign.