There are two spirit of God refers to, either the Father's presence, or the third person of the Trinity depending on the context. Here is a point made by an individual on one of my videos responding to Asher Meza:
"Israelite prophets never taught to Children of Israel that Holy Spirit is God. So how can Romans interpret wrongly? Also, Isaiah 61 mentioned clearly salvation can ONLY be given by God not servant,
This shows that the teaching spread by Romans about Triune God is indeed false."
There is one case where the Spirit does refer to a divine person and not simply the divine presence of the Father, read Ezekiel 11:1-5.
Also, No Christian disputes that only salvation can be given by God, but Jesus himself claimed to be God, and if he did, He gives salvation to his people. That I have written on elsewhere.
Read the following:
(The point about Isaiah 9:6 I need to rethink on).
I have written more articles on the subject of the Trinity which I would recommend the audience reading:
Hence, the belief in the Triunity of God is not false. Hope this answers the objection.