Again Heb 6 is about
falling away from the faith, not about committing a single sin and then repenting of it later and turning back to the Lord and being forgiven. You are trying to prop up a straw man argument by misrepresenting what falling away from the faith means in Hebrews 6. Nice try though.
You don't believe what the verses say. You want to so desperately to make them about man today (most likely because you are trusting in your work and not trusting His), but they are clearly not. Your first clue is who Hebrews is written TO. Anything? It's written to Hebrews! Secondly, addressing the content, you slide away from that too as it says it is impossible...read it and believe every word!
Hebrews 6:4 For it is impossible for those who were once enlightened, and have tasted of the heavenly gift, and were made partakers of the Holy Ghost,
Hebrews 6:5 And have tasted the good word of God, and the powers of the world to come,
Hebrews 6:6 If they shall fall away, to renew them again unto repentance; seeing they crucify to themselves the Son of God afresh, and put him to an open shame.
Hebrews 6:4 For it is impossible for those who were once enlightened, and have tasted of the heavenly gift, and were made partakers of the Holy Ghost,
Hebrews 6:5 And have tasted the good word of God, and the powers of the world to come,
Hebrews 6:6 If they shall fall away, to renew them again unto repentance; seeing they crucify to themselves the Son of God afresh, and put him to an open shame.
Impossible means impossible and a perfect example of a couple who were once enlightened and tasted of the heavenly gift who fell away were Ana and Sapp.
They, like the Hebrews, were only made partakers if what?
Hebrews 3:14 For we are made partakers of Christ,
if we hold the beginning of our confidence stedfast unto the end;
Whereas we are made partakers by the gospel (Ephesians 3:6 KJV) and that "of the grace of God (Acts 20:24 KJV) the moment we trust the Lord after hearing and believing the word of truth, the gospel of our salvation (Ephesians 1:13 KJV). It's a done deal where we are concerned!