I agree, changing hearts is paramount!
I did watch "Future Things", I will rewatch it since I don't remember what David is saying.
As for your question, I'm in no way a teacher, I don't have a gift for that at all, so I might just refer you to a website I'm starting to read that speaks on the preterist doctrine in depth. I don't want to say something that is not true, since we're all here to seek the truth. It would be foolish on my part to "teach" something when I'm really not a teacher.
This website answers questions about verses, like yours. Here is the article about 1 Thessalonians 4:13-18, if you want to read it: 1 corinthians 15 50 54 a preterist commentary (revelationrevolution.org) — https://www.revelationrevolution.org/1-corinthians-15-50-54-a-preterist-commentary (I'm still discovering the website, as I said, I'm starting to read it, we need to test everything).
In my opinion, Revelation was written before 70 AD, for the mere fact that back in the days, the temple of the Jews was the center of all the religious "system" (for a l ack of a better term ), it was very important for the Jews because, there, dwelt the presence of God. Everything revolved around the temple (offerings, sacrifices, feasts, etc).
Therefore, because there is never one mention of its destruction in any of the epistles (only in Matthew 24), I believe that to be a strong argument for it being written before 70 AD. I understand that it goes against the majority of the scholars out there, but I don't think scholars are the basis for my faith.
Also, there are so many time indicators ( 101 preterist time indicators (adammaarschalk.com) — https://adammaarschalk.com/2013/07/23/101-preterist-time-indicators/ ) concerning the end times being near to their time, that it just makes sense that God wouldn't tell believers back then that He'd come quickly in their generation (Matthew 24) and everybody needs to prepare, but 2000 years later He still didn't come. It makes no sense to me.
What made me consider preterism is the constant fear and passivity in some, not all, but a majority of Christians "waiting for Jesus to return", the fruits are weird to me, and also, the Bible wasn't written to us, it was written to the people back then. So John* clearly tells his audience 2000 years ago that it was the last hour for them, as in, it's coming. And Jesus ends the book of Revelation by saying that He'll come soon. I could go on, but that's not the topic. I'm just passionate haha :p
Again, I thank you for your help and your answers.