1 Cor 2:14 does not say “unregenerate person.” It says psuchikos, which means “soulish,” or “of the soul.” IE: a natural person, a person influenced by the world. There are Christians who live their lives that way… Any person, Christian or not, can change their thinking and become concerned about things of the spirit.
That’s not what the text says. It says “ye were sealed with that holy Spirit of promise.” Or “sealed with the promised Holy Spirit.” After we heard and decided to believe the Gospel, we were sealed with the Holy Spirit himself.
Have it your way, but your way does not harmonize with Eph 2:1-5.