Scripture is stacked against you. Certainly all Christians have the seed of the Holy Spirit within their spirit, otherwise they would be spiritually dead. But baptism or infilling of the Holy Spirit is an experience of a very different order and for a different purpose.
I've met many ex cessationists who believed your false teaching, my wife being one of them. Then at a later stage after crying out to the Lord were suddenly baptised in the Holy Spirit. Realising immediately how much they'd been lied to by their faithless leaders, and deprived of their inheritance.
Although it may happen simultaneously, scripture shows that immersion or the infilling of the Holy Spirit is a separate experience from being born of the Spirit.
Scripture also shows that being filled happens repeatedly to those who need or seek more of the Lord.
We know Peter and these people had already been filled with the Holy Spirit at Pentecost, yet here they are filled again.
Acts4v 31And they having prayed, the place in which they were assembled was shaken, and they were all filled with the Holy Spirit and were speaking the word of God with boldness.
We see Paul being initially filled with the Holy Spirit here.
Acts9v17And Ananias went away and entered into the house; and having laid the hands upon him, he said, “Brother Saul, the Lord Jesus, the One having appeared to you on the road by which you were coming, has sent me that you may see again and be filled of the Holy Spirit.”
And the filled again here-
Acts13v9But Saul, who was also known as Paul, filled with the Holy Spirit, fixed his gaze on him,
And if all Christians are already filled with the Holy Spirit, then Paul's command here is a complete waste of breath.-
Eph5v18And do not get drunk with wine, for that is dissipation, but be filled with the Spirit,
And of course the most notable example of someone being filled with the Holy Spirit as a second experience.-
Luke3v22and the Holy Spirit descended upon Him in bodily form like a dove, and a voice came out of heaven, "You are My beloved Son, in You I am well-pleased."
Jesus lived 30 years as the genuine Son of God, but was not filled or empowered by the Holy Spirit till his baptism. ie. a second experience.