Whats better Synthetic or Synthetic blend?

Use either one you want. If you use the blend I would change oil every 3 to 4,000 miles.

At first, the major duty is to use the oil that your vehicle instructions says. Most of the cars nowadays need to use full synthetic oil for high lubrication. But synthetic blend can also be used. This article below can be helpful if you need to know a detailed comparison and decide one for you regarding these two- blend and the full synthetic. https://www.autokingx.com/motorcraft-full-synthetic-vs-blend/