To the OP . . .
Ephesus was facing fragmentation, in false apostles, and removal for having left their first love.. Jesus introduces Himself as the One Who is holding them all, never left them, and is in all their midst, He gives unity, not a false unity with false teachers.
Smyrna was facing death, Jesus introduces Himself as having power over death.
Pergamos - bad marriage - is a mixture of true and false, Jesus is the sharp two-edged sword that divides.
Thyatira, the "prophetess" is warned agains judgment, and her children with judgment, by He Who has eyes like fire, and feet like brass in the furnace, tokens of judgment.
Sardis is warned that they are not continuing in what they began, by He Who holds the messengers of the churches, and the 7 Spirit, He provides leading outside and inside by His ministers and the gift of His Spirit, so we can complete our race.
Philadelphia, the One Who is Holy and True, and Who is victorious over all, though they be weak, He assures them of victory.
To the Laodiceans, the Preeminent, the Faithful and True, invites them to come to Him, and to realize the emptiness of what they don't even actually have.
My impressions only.
Much love!