In the New Testament, He is called "Jesus Christ" 185 times, and "Christ Jesus" 69 times. So why could you never see any apostle calling Him "Jesus Christ?" Paul wrote, (for example):
(Rom 1:1-3 NKJV) Paul, a bondservant of Jesus Christ, called to be an apostle, separated to the gospel of God which He promised before through His prophets in the Holy Scriptures, concerning His Son Jesus Christ our Lord, who was born of the seed of David according to the flesh,
Sorry, I don't understand what you mean by "it can't be two flesh Jesus died or Christ." "Jesus" and "Christ" refer to the same glorious Person. This is clear from Paul's preaching:
(Act 18:27-28 NKJV) And when he desired to cross to Achaia, the brethren wrote, exhorting the disciples to receive him; and when he arrived, he greatly helped those who had believed through grace; for he vigorously refuted the Jews publicly, showing from the Scriptures that Jesus is the Christ.
It wasn't "Jesus or Christ" who died on the cross. It was Jesus Christ. Paul wrote:
(1Co 2:2 NKJV) For I determined not to know anything among you except Jesus Christ and Him crucified.