To answer your question, "This would mean that 6000 years is not until 2240? Can someone help me understand why this is not correct? And furthermore why 2023 would rather be 5993 yrs since creation?"
Scripture (KJV) teaches 3 timelines: the time past, the last days, and the latter times (end times). Each of these timelines begin at sunset of Elul 29, which begins Tishri 1, and ends when a certain event occurs in the future at sunset of Elul 29.
The time past timeline began when Mankind (Adam/Eve) sinned on Elul 29, and then God showed them His mercy on Tishri 1 (Gen. 3:8, 21). The time past timeline ended (which ushered in the last days timeline) when Jesus turned 30 at sunset of Sept. 19/20, AD 27 Tishri 1, as scripture proves He was born on Sept. 11, 3 BC Tishri 1 (sometime between 6:18 p.m. and 7:39 p.m.; Rev. 12:1-2). Jesus was then baptized "being about" (not quite 30) in the spring (c. March 10, AD 27 Adar 13), and because He wasn't 30, He could not preach/teach in Israel until He turned 30 according to the law (Num. 4). He began preaching/teaching the morning after He turned 30 (Sept. 20, Tishri 1, AD 27), which was after He was tempted of the devil in the wilderness on Sept. 19, AD 27 Elul 29, which occurred about six months after He was baptized. Jesus was then tried and crucified on April 5, Nisan 14, AD 30.
The time of His ministry was: March 10/Adar 13, AD 27 - April 5/Nisan 14, AD 30 = 3 yrs, 26 days (from His baptism) or
Sept. 20/Tishri 1, AD 27 - April 5/Nisan 14, AD 30 = 2 yrs, 2 months, 16 days (from when He turned 30).
After His death and resurrection, yet prior to His ascension, He commissioned the church to preach the gospel. According to scripture, the last days timeline ends when the church collectively comes to the full to believe another gospel, which ushers in the latter times timeline (end times). Scripture proves the end times began at sunset of Sept. 29/30, 2008 Tishri 1. On the latter timeline lies a 7-yr period called the latter days, which begins fourteen years from the beginning of the latter timeline, which began at sunset of Sept. 25/26, 2022 Tishri 1, and ends at sunset of Sept. 09, 2029 Elul 29.
According to scripture, it's within the latter days (7-yr period) when a myriad of events shall occur: the Latter Rain (second outpouring of the Holy Spirit), worldwide evangelism, tribulation (1st of two), rapture of His Church, great tribulation (2nd of two), Ezekiel's War, remnant Jews come to repentance and are saved, and then comes His wrath, which is reserved for the ungodly and the disobedient children. Note: tribulation is not 7-yrs, rather tribulation takes place within the latter days.
It's my understanding, based on scripture and others, that 2030 is the year when the Millennial Kingdom of Christ begins.