I don’t understand why it would matter that he is speaking to “the saints which are at Ephesus”. In verse 13 he recounts how they came to be in Christ. They were sealed in him with the Holy Spirit when they believed. There is no mention of water baptism. Certainly he could have said they were sealed in him with the Holy Spirit when they believed and were water baptized, but he didn’t say that.
When are we sealed and cleansed? We are sealed in him by the Holy Spirit when we believe. When we have been sealed in him we are cleansed by his blood.
“In him you also, when you heard the word of truth, the gospel of your salvation, and believed in him, were sealed with the promised Holy Spirit,”
Ephesians 1:13 ESV
https://bible.com/bible/59/eph.1.13.ESV
“In him we have redemption through his blood, the forgiveness of our trespasses, according to the riches of his grace,”
Ephesians 1:7 ESV
https://bible.com/bible/59/eph.1.7.ESV
Acts 2:38
“Kefa answered them, “Turn from sin, return to God, and each of you be immersed on the authority of Yeshua the Messiah into forgiveness of your sins, and you will receive the gift of the Ruach HaKodesh!”
Acts of Emissaries of Yeshua (Act) 2:38 CJB
https://bible.com/bible/1275/act.2.38.CJB
This version does a few things that I believe give a better representation of the original language. It translates baptistheto as be immersed. This makes it less likely for the reader to assume water baptism. No water is mentioned. It also translates epi as ”on” instead of ”in”. Epi means on. Then finally it translates eis as “into” which is its primary meaning.
This helps us see that the verse actually says “repent and be immersed on the authority of Jesus Christ into forgiveness of your sins”. Repent/metanoesate simply means to have a change of mind and a person who comes to believe has had a change of mind.
Now remember those two verses above Ephesians 1:7 and 13. We are sealed/immersed into Christ when we believe and in Christ we have forgiveness of sins through his blood.
Exactly the same as Acts 2:38.
Acts 22:16
Same concept as above. Immersion into Christ, not water immersion.
1 John 5:1 is true.
“Everyone who believes that Jesus is the Christ has been born of God, and everyone who loves the Father loves whoever has been born of him.”
1 John 5:1 ESV
https://bible.com/bible/59/1jn.5.1.ESV