Selfishness is not a four letter word

Galatians 5:20 says that The acts of the sinful nature are obvious:
sexual, immorality, impurity and debauchery; idolatry and witchcraft; hatred,discord, jealousy, fits of rage, selfish ambition, dissensions, factions and envy; drunkenness, orgies, and the like. I warn you, as I did
before,


that those who live like this will not inherit the kingdom of God.





Christians do good works because they have faith in God.




And if you have faith, then you go to heaven.




So suppose someone does good works for others; this initially seems unselfish.




One does good works because he/she has faith that he/she (the
individual will go to heaven.




So this individual does unselfish acts for others on earth ultimately in order to commit the selfish act of getting into heaven.




Ultimately he/she is consciously unselfish because he/she is
unconsciously selfish.



But isn't selfishness an act of the sinful nature according to Paul writing in Galatians 5:20?


IS THIS NOT A BLATANT CONTRADICTION IN THE BIBLE?