I don't really see much continuity in jumping from 1 Peter to 2 Peter. I was expecting you do something more along the lines of continuing with the rest of 1 Peter 4. I'm also not seeing how 2 Peter undoes what he said in 1 Peter 4:6. But maybe I'll see it differently later on.
Of course you don't see any continuity because you didn't even look. You saw what you wanted to see only what lines up with you UR assumptions/presuppositions.
1 Peter 4:6
6 For for this cause was the gospel preached also to them that are dead, [NIV, now dead] that they might be judged according to men in the flesh, but live according to God in the spirit.
This seems to be straight forward when read in isolation. It seems to be saying the dead will be saved but…. How could the dead be judged according to men in the flesh when they were dead?
Let’s read further in Peter and see what else Peter says about the fate of the unsaved.
2 Peter 2:1
But there were also false prophets among the people, just as there will be false teachers among you. They will secretly introduce destructive heresies, even denying the sovereign Lord who bought them—bringing swift destruction on themselves.
When Peter wrote his second book did he forget what he wrote in the 1st book? “bringing swift destruction on themselves” doesn’t sound like being saved by Jesus’ preaching to me.
2 Peter 2:4-5
4 For if God did not spare angels when they sinned, but sent them to hell, putting them in chains of darkness to be held for judgment;
5 if he did not spare the ancient world when he brought the flood on its ungodly people, but protected Noah, a preacher of righteousness, and seven others;
Here is what Jesus said about this.
Matthew 25:41
41 Then shall he say also unto them on the left hand, Depart from me, ye cursed, into everlasting fire, prepared for the devil and his angels:
Like the angels, vs. 4, the unrighteous will be sent to hell to be held for judgment. Also see 2 Pet 2:9 below.
2 Peter 2:9
9 if this is so, then the Lord knows how to rescue the godly from trials and to hold the unrighteous for punishment on the day of judgment.
“rescue the godly from trials” and “hold the righteous for punishment” A distinction between two groups does not sound like being saved by Jesus’ preaching.
2 Peter 2:12
12 But these people blaspheme in matters they do not understand. They are like unreasoning animals, creatures of instinct, born only to be caught and destroyed, and like animals they too will perish.
“will perish like animals” not saved by Jesus’ preaching
2 Peter 2:17
17 These people are springs without water and mists driven by a storm. Blackest darkness is reserved for them.
“Blackest darkness is reserved for them,” not being saved by Jesus’ preaching.
2 Peter 2:20
20 If they have escaped the corruption of the world by knowing our Lord and Savior Jesus Christ and are again entangled in it and are overcome, they are worse off at the end than they were at the beginning.
“worse off … than they were at the beginning “ not being saved by Jesus’ preaching.
Hope this helps.