You shouldn't brag as if you understand that Scripture, when you show you do not, but only pull a verse out of that and push traditions of men.
The ACTUAL meaning of what Jesus said there:
Luke 17:20-24
20 And when He was demanded of the Pharisees, when the kingdom of God should come, He answered them and said, "The kingdom of God cometh not with observation:
21 Neither shall they say, "Lo here! or, lo there!" for, behold, the kingdom of God is within you.
Lord Jesus was pointing to them about THIS PRESENT WORLD, not the world to come when His literal Kingdom will be manifested de facto upon this earth with His return and literal reign on earth.
So during this PRESENT WORLD TIME, Christ's Kingdom is 'within' those of His servants here on earth only, meaning by The Holy Spirit in them through their Faith. But that is going to change in the future with Christ's future return, as written in many, many other Scriptures. So it's silly to even think about forgetting that future part.
22 And He said unto the disciples, "The days will come, when ye shall desire to see one of the days of the Son of man, and ye shall not see it.
23 And they shall say to you, "See here; or, see there": go not after them, nor follow them.
Jesus further points out the difference of THIS PRESENT WORLD TIME to His disciples. Even they will desire to see one of the days of Christ's future Kingdom to come, and shall not see it IN THIS PRESENT TIME. And THEREFORE... If... any man during this present world comes up to you and says something like, "See here, or, see there", trying to say His Kingdom has come IN THIS WORLD, Jesus is saying DO NOT FOLLOW THOSE MEN! That warning comes from His Olivet discourse about the pseudo-Christ coming at the end of this PRESENT WORLD. He warned to not believe it if someone says, "Lo, Christ is here, or there" (Matthew 24:23-26).
24 For as the lightning, that lighteneth out of the one part under heaven, shineth unto the other part under heaven; so shall also the Son of man be in His day.
KJV
Exact same idea He gave in His Olivet discourse right after His warning about some saying He is here, when it will be a pseudo-Christ having come instead. The idea of seeing lightning shine across the sky is about the whole world will know and see Christ's true coming in the clouds. No man will have to tell us He has come.
No, that prayer is a PETITION for His future Kingdom to come, not that it has already come.
If the church you are attending is teaching that Christ's Kingdom is already manifest here today on earth, that it has come, and there is nothing else to establish, then those are deceived, and are actually preparing their congregations for the coming false-Messiah that is to come first prior to Lord Jesus' coming.
The Ezekiel 40 thru 47 chapters reveals a Millennial sanctuary in the area of Jerusalem is where Jesus will reign with His elect from starting at His future return. And with that sanctuary will manifest a return of God's River of the Waters of Life, and the Tree of Life, both mentioned at the end of Revelation.