2. Syphilis was originated in Africa and through slavery was brought to Spain and Portugal (Mercuri et al., 2022).
3. Syphilis existed in Europe and the Americas for a long time. But it existed in 4 stains and was very rare or misdiagnosed as other illnesses.
According to Tampa et al., (2014), researchers who did a studied all the available genetic and historical evidence on the origin of syphilis, the most likely answer is that syphilis was an endemic disease (an infection that regularly happens in a area or community) in the Americas that evolved from a non-venereal ancestor, and was introduced to Europe by Columbus and his men in 1493 when they visited the new world.
Despite this their evidence also suggests that syphilis may have existed in other parts of the world before Columbus, but was either rare or misdiagnosed as other diseases.
So basically a combination of all three hypothesis is probably closer to the truth.