If a partial preterist position is accepted, the rest of the case for hell and brimfire for unbelievers is very small. The overall thrust of Old and New Testaments is obviously universalist. “Uniting all things by the blood of His cross.” “Every knee shall bow and every tongue confess” “As in Adam all die, so in Christ shall all be made alive.” “If I be lifted up, I will draw everyone to Me”, etc, etc.
The reason some don’t yet believe is that they have not yet been rescued from the god of this world who has blinded their minds to keep them from seeing the light of the gospel of the glory of Christ. Jesus came not to condemn the world, but so that whoever believed in Him (and whenever) that they should (from that time) no longer be perishing but have eternal life. (the present continuous tense of “be perishing” is the one used in John 3:16 in the Textus Receptus.)
The big picture makes so much better and more wonderful sense with Biblical Universalism. True you do have to get back to the original language meanings since many modern translations are paraphrases in which mistaken theology is presented.
True, you do have to account for how there could be so much error in mainstream Christendom.
And true, you have to reject the worldly notion that justice is about retribution, and see that God’s justice is actually about putting things right again (closely related to restorative justice and cousin to social justice).
And true you do need to believe in God’s grace strongly enough to follow the Spirit into all the truth.
An excellent site on Biblical Universalism is www.tentmaker.org. However, tentmaker.org is site has come out of a Substitutionary Atonement school of thought, and doesn’t reflect the ancient function of blood sacrifice newly rediscovered by Rene Girard.