At a bare minimum Tacitus confirms Jesus was a real person who lived in Judea, was executed under Pontius Pilate, and had group of followers called Christians who believed in a “mischievous superstition” that broke out after his execution. I’m trying to think of a good reason not to include Biblical sources, like Paul’s epistles (7 of which are undisputed), when trying to ascertain the beliefs of those who followed this “mischievous superstition” mentioned by Tacitus, but I can’t think of any.

What do you mean by right and wrong? Who determines what is right and what is wrong?

The existence or non-existence of Santa has nothing to do with whether it is reasonable to believe Jesus was physically raised from the dead. You can’t use Santa to disprove Christianity.

There is excellent historical evidence that Jesus of Nazareth was a real person who lived in the first century and died by crucifixion. This is well attested in Biblical and non-Biblical sources. Jesus-mythers are few and far between in serious academic circles.

What do you mean by “tangible evidence”? There are plenty of philosophical arguments for God, some even using evidence from science as a premise (like the Kalam Cosmological Argument).

You are correct that God is changeless from a moral perspective. God might change in relation to things like time, for example, knowing today is Dec. 24th, and tomorrow knowing it is Dec 25th, but the God of the Old Testament was morally perfect and the God of the New Testament identically morally perfect.