Is there any hope for salvation after the Rapture?

II Thessalonians 2 says that God will send strong delusion so that those who have not loved the truth in the age of grace will be deceived and damned after the rapture.  Those would be people who have heard the gospel of grace and did not choose to believe and be saved.

When you read Revelation such as chapter 7, there seems to be many who will get saved during the tribulation.  It must be those who had not heard the gospel of grace in this age.  However, those in the tribulation must endure to the end to be saved into the Kingdom, or as Revelation 2&3 says “overcome.”