OK, using my “litmus test”, is Jesus going to say to you or me, at the GWTJ, “Sorry, you had that hell thing wrong. You are not saved.”
My take is, no. So it falls under 2 Timothy 2.
Regarding that lake of fire stuff, I’ve argued this as much as is necessary in the past. I know what I believe and I know what I teach my students. And I can back it up.
The “Goldilocks” argument, for me, is Jewishnotgreek.net. That is, it’s not exhaustive, and it’s not overly simplistic. It covers all the bases enough for most people.
The fact that souls of penitent faith in the Lord and Savior Jesus can be either ignorant or wrong about some doctrines (from predestination, to the perpetuity of Pentecostal gifts, to female pastors, etc.), and still be saved (if obeying light they have) simply does not relegate these teachings to be akin to issues of personal liberty, and does not place them in 2 Timothy 2:
Of these things put them in remembrance, charging them before the Lord that they strive not about words to no profit, but to the subverting of the hearers. (2 Timothy 2:14) But foolish and unlearned questions avoid, knowing that they do gender strifes. (2 Timothy 2:23)
And, if anything, the teaching on the afterlife is too clear and thus opponents of eternal punishment engage in laborious work in trying to disallow it.