This web site is by a former Modalist, Steven L. Hitchcock, and he has a dedicated page addressing some arguments against Modalism.

Go to this page on this site: Former Modalist

Listen to these sermons on the Oneness of God and the Trinity:

October 18, 2020 – Mark 12:28-34

October 25, 2020 – Mark 12:28-34, 2