The early Christians had the apostles themselves who testified to Christ, so they didn’t need the written word like we do (and that is WHY God had them write down their testimony of Him) and they did have the Old Testament prophets which as in Luke 16:31 “And he said unto him, If they hear not Moses and the prophets, neither will they be persuaded, though one rose from the dead.”
Which (the O.T. also testified about Christ, I would recommend especially reading Isaiah)..
It’s not a very logical argument you make.
yes it is logical....the holy spirit saves without the written word. The written word can facilitate that, yes...but not always needed.
You are severely limiting salvation and how it happens often.