Fundamentalist Biblical Universalism
I know that there are a lot of people here who reject things like Biblical Inerrancy and Sola Scriptura and such, but quite a few of the Christians you talk to are fundamentalists, and many of them aren’t going to listen to arguments that aren’t based on these ideas. When you talk to these particular Christians, I think you’ll find my free Biblical Universalism eBook helpful to recommend to them, because it uses only the King James Bible (which a lot of these Christians also insist on using) to prove the salvation of all. In this book, I’ve gone over basically every “proof text” I’ve ever heard used to defend both Infernalism and Annihilationism, in order to demonstrate that these passages don’t actually contradict Universalism at all (and, in many cases, actually support the doctrine).
I should also say, even if you’re not a Biblical Inerrantist, you might still find the scriptural interpretations and arguments in the book useful for your own discussions with the various fundamentalist Christians you come across.
You can find the links to the newly updated PDF and zipped ePUB versions of the eBook here: https://www.universalism.ca