Straits of Magellan vs. Cape Horn

Which passage was more dangerous to a ship? In the days of sail, the trip around Cape Horn was feared by mariners. Sailors rounding the cape encountered fierce winds, high seas, and frequent storms-many times,ice storms would cause a sailing ship to become topheavy and capsize. In contrast, the Straits of Magellan are fairly safe waters-except for the strong currents and dangerous island at the Pacific side (the “Twelve Apostles”).
My question: were ther any tugboats in the straits, so sas to tow sailing ships through? Or was rounding the Cape (even though dangerous) preferred to navigating the straits?

Based on my reading, the route south of Cape Horn was preferred. The Straits gave some shelter from stormy conditions, but along this route dangerous land was always fairly near and ready to wreck a ship that had trouble or became uncertain of its position.

Wiki has this to say:

So according to Wiki, the Cape route (Drake Passage) was preferred, even though it was discovered after the Straits route, which indicates the answer you desire.

I’ve not heard of such in the SoM during the sailing ship era. And typical merchant sailing ship economics would not have allowed for this sort of expense.

What would a tugboat be in that era? A smaller sailing vessel? How does that work? A rowing vessel?

Typically the solution at the time was not to employ tugboats, but rather dedicated pilots who knew the area in question and could thus avoid the trouble spots. Would there have been a career in being a SoM pilot, commuting between two cities in South America?

Well, the era of powered tugboats overlaps that of merchant sail. But deepwater sailors typically had both the skills and tradition to avoid much use of them.