You agree with St. Paul that there is a Trinity "The grace of our Lord Jesus Christ, and the love of God, and the communion of the Holy Ghost, be with you all" (2 Corinthians 13:13) .
As you are aware, the muslims intend that the object of worship is the same 'God of Abraham' as worshipped by the jews and Christians, however both muslims and jews have a wrong understanding of God's nature (unity). The Church proclaims the fullness of the Christian revelation in the Trinity, that the unity of God is expressed in the mystery of the three divine Persons as essential Christian belief.
Here is a one minute video about muslims converting to Christianity https://www.youtube.com/watch?v=QgWXoSs0GSY you can look up a longer video by Ismail Youssef on his conversion story.
Jesus didn't establish numerous conflicting denominations. Jesus established one Church. Jesus prayed that his disciples “may be one, even as you, Father, are in me and I in you, that they also may be in us, so that the world may believe that you have sent me” (Jn 17:21).
The Judeo-Chrislam Papal totalitarianism, got it.
Those that intend to follow the 'God of Abraham' are invited to know the fullness of Christian revelation in the Trinity. Unlike human political systems, the reign of God inaugurated in Christ, is a Kingdom. The Church is the Kingdom of Christ already present in mystery and its growth is the growth of the Kingdom itself.