Your references from Colossians and Hebrews are identical, and speak of “What we believe”... not what we do or fail to do.
Your reference from 2 Peter however is quite different.
“They” needs to be defined, and we find that definition by bringing into context the previous verses starting in verse 9:
2:9 - “The Lord knoweth how to deliver the godly out of temptations, and to reserve the unjust unto the day of judgment to be punished: But chiefly them that walk after the flesh in the lust of uncleanness, and despise government.”
Verses 10-19 further defines “they”, and as you read through it, it becomes very clear to whom God is referring;
Quite simply, “they” are those who are being preserved for judgment... those who are openly defiant of God and what He stands for. It is their knowledge of the truth that would make it better for them to have not been born to begin with, because their punishment is that much worse than those who simply failed to find the Truth.
I submit that those who are being defined as “they” are quite different than those who lose or lack faith.
Furthermore, the premise that “they had previously escaped the corruption of the world” refers to born again Christians is grammatically false when placed in context with the previous verse;
In verse 19 we see this: “While they promise them liberty, they themselves are the servants of corruption: for of whom a man is overcome, of the same is he brought in bondage. “
“They” are the deceivers promising liberty to those (them) whom they seek to corrupt... and the following verse 20 which you referenced is a paradoxical argument which illustrates that “they” indeed have NOT escaped the pollutions of the world BECAUSE they are themselves servants of corruption.
Nobody is yet “saved” because that salvation lies in the spiritual rebirth Yeshua described to Nicodemus in John Ch 3, which rebirth enables the re-born to travel invisibly through our present dwelling place like the wind, as described clearly in verse 8:
John 3:
[6] That which is born of the flesh is flesh; and that which is born of the Spirit is spirit.
[7] Marvel not that I said unto thee, Ye must be born again.
[8] The wind bloweth where it listeth, and thou hearest the sound thereof, but canst not tell whence it cometh, and whither it goeth: so is every one that is born of the Spirit.
1Peter 1:
[9] Receiving the end of your faith, even the salvation of your souls.
Hebrews 4:
[1] Let us therefore fear, lest, a promise being left us of entering into his rest, any of you should seem to come short of it.
[2] For unto us was the gospel preached, as well as unto them: but the word preached did not profit them, not being mixed with faith in them that heard it.
11] Let us labour therefore to enter into that rest, lest any man fall after the same example of unbelief.
Philippians 2:
[12] Wherefore, my beloved, as ye have always obeyed, not as in my presence only, but now much more in my absence, work out your own salvation with fear and trembling.
We can “know that we will be saved” if we so endure.
To that end, Yeshua writes his commandments “on the fleshly tables of their hearts.”
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Let's post the WHOLE thing...
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. 2 Many will follow their depraved conduct and will bring the way of truth into disrepute. 3 In their greed these teachers will exploit you with fabricated stories. Their condemnation has long been hanging over them, and their destruction has not been sleeping.
4 For if God did not spare angels when they sinned, but sent them to hell,[a] putting them in chains of darkness[b] 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; 6 if he condemned the cities of Sodom and Gomorrah by burning them to ashes, and made them an example of what is going to happen to the ungodly; 7 and if he rescued Lot, a righteous man, who was distressed by the depraved conduct of the lawless 8 (for that righteous man, living among them day after day, was tormented in his righteous soul by the lawless deeds he saw and heard)— 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. 10 This is especially true of those who follow the corrupt desire of the flesh[c] and despise authority.
Bold and arrogant, they are not afraid to heap abuse on celestial beings; 11 yet even angels, although they are stronger and more powerful, do not heap abuse on such beings when bringing judgment on them from[d] the Lord. 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.
13 They will be paid back with harm for the harm they have done. Their idea of pleasure is to carouse in broad daylight. They are blots and blemishes, reveling in their pleasures while they feast with you.[e] 14 With eyes full of adultery, they never stop sinning; they seduce the unstable; they are experts in greed—an accursed brood! 15 They have left the straight way and wandered off to follow the way of Balaam son of Bezer,[f] who loved the wages of wickedness. 16 But he was rebuked for his wrongdoing by a donkey—an animal without speech—who spoke with a human voice and restrained the prophet’s madness.
17 These people are springs without water and mists driven by a storm. Blackest darkness is reserved for them. 18 For they mouth empty, boastful words and, by appealing to the lustful desires of the flesh, they entice people who are just escaping from those who live in error. 19 They promise them freedom, while they themselves are slaves of depravity—for “people are slaves to whatever has mastered them.” 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. 21 It would have been better for them not to have known the way of righteousness, than to have known it and then to turn their backs on the sacred command that was passed on to them. 22 Of them the proverbs are true: “A dog returns to its vomit,”[g] and, “A sow that is washed returns to her wallowing in the mud.”
It mattereth not who the THEY are, for if THEY (Verse 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.
Are you trying to make the point that ONLY 'false teachers' will be 'worse off'?
I find that an improper interpretation of the passage.