The way I see it, there are only two "gods" in existence who desire our worship. One is the true God, who deserves it and the other is a pretender who is trying to steal it by deception.
The true God is the one who determines what worship is acceptable to him. The pretender will dish up all manner of "look-alikes" and fakes to fool the most discerning worshipper. He gives people what they want and demands very little in return. He uses ritual to make people feel comfortable and to give them a sense of belonging. He provides ego stroking and rewards with little self sacrifice. He makes sure that people can have their cake and eat it too. All he requires is that you worship does not go to the true God.
The God of the Jews was originally the true God, Yahweh. But because of their constant disobedience and breaking of his laws and covenants, after they orchestrated the death of their Messiah, the true God abandoned them. (Matt 23:37-39)
He virtually handed them over to the pretender to carry on with their wayward course. They have no idea that it ever occurred.
Islam is based on the beliefs of Abraham's first son, Ishmael, who was born to an Egyptian hand maiden. So even though these "Abrahamic" faiths had a common origin, they all went in completely different directions.
So who is the true God of the Bible accepting worship from today? Islam? Judaism? Or Christianity? It depends on whose beliefs you accept and follow. Each are convinced that their faith is the correct one...but what does their conduct show?
Muslims accept Jesus as a prophet, but not as the son of God, nor do they believe in his death as a ransom for mankind. There is much bloodshed in its past and present practise.
Jews do not accept that Jesus was the promised Messiah because according to their leaders, Jesus did not fulfill the messianic prophesies. He rejected the teachings of their leaders and castigated them. Jesus did not have a good word to say about the teachings of the Pharisees. So they whipped up a hate campaign against him and his disciples.
Christianity (Christendom) also claims to worship the God of the Bible, but then conducted themselves contrary to all his teachings. They even blasphemed the Father by putting Jesus in equal place with his God.
So how does one make sense of all this and what are the identifying marks of a true believer? In a word....PEACE. it's very simple...only God's true worshippers have genuine peace, in their lives and in their congregations, despite the horrors of living in this world.
It comes as a direct result of God's spirit being operative in their lives and in their work. They do not go to war and they do not spill blood in the name of their God. They love one another as Jesus loved them. They love even their enemies as Jesus taught them to do...conquering evil with good. They are out preaching the good news of God's kingdom, rather than propping up the corrupt rulerships of this world. They are "no part of this world" whom the apostle John said is ruled by the pretender. For this they are hated and persecuted. (John 15:18-21; 1 John 5:19; 2 Cor 4:3, 4)
That kind of narrows down the field in my estimations. The truth is, neither Islam, nor Judaism nor Christendom (which is not to be confused with Christianity) worships the true God....they have been fooled into thinking they do. The one who can "blind the minds" of people has the ability to cut off all reasoning ability when it comes to worship.
Many have even thrown God away because of what religion has done....but the pretender doesn't care if you believe or not.....as long as he has you distracted by the religious confusion he has created as a smoke screen to mask the truth. You are not worshipping the true God...and that is all that matters to him.
Genuine truth seekers need not worry however. No one can come to the son without an invitation from the Father. He will see to it that everyone has an opportunity to hear the truth and if he sees a positive response, he will "draw" that person. (John 6:44; Matt 24:14)
There is one God....but not many have found him. (Matt 7:13, 14, 21-23)