Santa Claus is a tale based on truth of a man named Saint Nicolas who actually lived. It is more of a legend that has developed progressively over time and is not immediately believed after the saint died. Jesus was immediately worshiped as God. Now, speaking of God, it’s better to speak of Jesus who claimed to be God. His story was written within two to three decades of His death with no time for legend to develop. There’s no comparison. This type of argument is a false equivalency. The apostles denied they were writing myth or fairy tale (cf. 2 Pet. 1:16). He was a historical person, not a myth with much secular corroboration.
It is written that His resurrection proves His deity (cf. Acts 17:31; Romans 1:4). Now, many people wanted Him to prove His claim, so He rose from the dead to prove it and this is arguably the most attested fact of antiquity “with many infallible proofs.” (cf Acts 1:3). Also, the fact the apostles died as martyrs and eyewitnesses is compelling evidence: people do not die for a known lie. Volumes could be written of all the circumstantial, historical. literary, legal, and testimonial evidence of this historical fact.
No one has ever successfully refuted the facts that support it like the fact of the empty tomb, over 500 eyewitnesses, the removed stone, the changing of the Sabbath, the growth of the church, the New Testament, the undisturbed graveclothes, the conversion of the apostles (especially of Paul), to the transformation of the Roman Empire from paganism and barbarianism. Christ is regarded as the central figure in Western history and civilization and not just its biggest revolutionist.
Also, just for the existence of God, there are philosophical and logical arguments and scientific evidence. One can not believe due to a lack of evidence.