For example, the church will be raptured. True, this promise is given to the church in Philadelphia, but not to any of the other six churches.
Yes, that promise was given to the church at Philadelphia, but did you check to see if that church got physically whisked away when persecution came? No such thing occurred, otherwise that would have reported by historians. There's a letter written by the church of Smyrna that gives this account to another church, reporting that 12 of those martyred where from the church of Philadelphia along with Polycarp.
So what did Jesus meant by His promise is that He will keep them in their faith intact and they won't fall away from Him when persecution (the hour of trial) comes.