For example the woman who founded the Shakers, she claimed to be Christ. Her name was Ann Lee. So she was a false Christ.
Or the man who founded the International Ministry Growing in Grace, he claimed to be Christ, and since he taught a form of modalism, he also claimed to be the Father. He taught that sin is impossible today, nobody sins no matter what they do. So people are saved by faith only, in God, who was de Jesus Miranda. He was worshiped by hundreds of thousands, mostly in Latin American countries. After he died several years ago, his movement split into several competing sects, with various beliefs. So he was a false Christ.
Or the man, Dialungana, who succeeded the false prophet Kimbangu after he died, that man claimed to be Christ returned. He died too, but he is still worshiped by millions in the Kimbanguist Church, found mostly in the Democratic Republic of Congo, but also in surrounding countries. So he too was a false Christ.
Or the man Sergey Torop, who calls himself Vissarion, he calls himself Christ, he says he is the reincarnation of Jesus, therefore the Word of God, but not God. He has tens of thousands of followers all around the world, most of whom live in his settlement in Siberia, his church is called the Church of the Last Testament. So he too is a false Christ.
Or Simeo Ondetto decided he is the new incarnation of Christ. He leads about a million people, mostly in Kenya, in a church called Legio Maria of African Church Mission. This is an offshoot of the Catholic church. So he is a false Christ.
Or the man called Christ Ahasahngong, he claimed to be Christ, he founded the World Mission Society Church of God, which still has many thousands of members, mostly in South Korea. He died but his church continues. So he too was a false Christ.
Even Apollo Quiboloy could be called a false Christ, he claims he is the Son of God, which title he allegedly inherited from Jesus Christ. He leads the Kingdom of Jesus Christ, the Name above Every Name, with headquarters in the Philippines.
Then there is Olumba Olumba Obu, the son of the Supreme Holy Father Olumba Olumba Obu, who claims to be God the Father and his son claims to be reincarnation of Jesus Christ, and a woman is the Holy Spirit, so the whole Trinity is now incarnated on earth, as 3 Nigerians, they lead the Brotherhood of the Cross and Star, with about 2 million members in many countries, but most are in Nigeria and Ghana. They have very strict salvation requirements, like no use of medicine, don't eat meat or dairy, wear only white robes, don't wear jewelry or even watches, very tough fasting requirements, etc., hard to obey it all, but if you fail, so after death you will get reincarnated. So there is another false Christ.
And of course there are plenty of people who claim to be Christ but have very few followers, or none.
So Mt. 24:23-24 has been fulfilled by many false Christs.
Those are the false Christs, not some preaching that Christ is the second person of the Trinity, or of the Binity, or that Christ is the Father, or that Christ is not God, such theories could be true or not, the Bible does not reveal which of these theories, if any, are true or not. We can't know the ultimate nature of Christ, since he told us in Luke 10:22, that nobody knows who the Son is, except the Father.