I have generally just taken the existence of Jesus as a given
I think most people were the same. I was. Our default is to believe what we are told, especially if told by >= 3 people (a heuristic that is good to know if you want to convince someone of something).
In one sense it doesn’t matter much because even assuming he existed, there is IMHO very little reliable evidence about what he said or did. Scholars widely believe that the eucharist, the feeding of the 5000 and the sermon on the mount were later additions to the story.
It is worth noting the trend here. Over time the historicity of biblical figures has eroded as older figures are gradually accepted as legendary. Usually this process occurs by the time honoured method of “science advances funeral by funeral”. A new generation comes through who accept e.g. tha Abraham or Moses were mythical figures.