The seven churches are jointly known as the Asia Minor churches of John's day. The writer John clearly says the next inside Revelation chapter 1 vs 10-11:
The above mentioned are a concise and clear directive from Jesus also John, as He describes Himself as the"Alpha and the Omega, the First and the Last". You can browse https://www.soh.church/ to know more about church services.
The Lord directs John to those particular churches, all which span a church era of approx. 90 decades, in the time of John's writing.
If we want to think these churches are gentile and recognized following the death and resurrection of Christ afterward he's writing these churches across 94 (AD) and based on powerful and consistent historic church customs, the Apostle John ministered in a minimum of one of the churches, Ephesus.
The sins of the church these days are represented by every Asia Minor church of John's day, this perhaps why Jesus focused on those 7 churches, realizing that the “sinner" of their church from beginning, growth and death would be symbolized by those seven churches of Asia Minor.
The First and the Last", these phrases might not just represent Christ as the savior of the Earth, from birth to death to resurrection, it could encircle the Pentecostal Church of Acts chapter two from birth to death to rapture, let us examine the Acts chapter two Church era over the previous 1900 decades and what exactly the Asia Minor churches can also signify.