Not canon This series is not canon as it goes at odds with the original Witcher lore originally created by Andrzej Sapkowski.
For example, in the original Witcher universe, the very first witchers were created by the Human race in an attempt to create mages from non-magically gifted people. The experiment was considered a failure since the amount of magical powers gained was considered insignificant, and those human witchers were exiled. While they were not good at magic, they did become more strong and dexterous, so after a time they formed their own guild and started specialising in exterminating dangerous monsters for profit. All witchers ever created belong to the Human race, there were never any Elf or Dwarf or Gnome Witchers. This is the original lore as created by Sapkowski.
While this fan fiction created by Netflix implies the first Witchers were created by Elves for the purposes of overthrowing an empire, way before the arrival of the first Humans into the world.
Also the culture of elves was depicted terribly in this adaptation, there is nothing elven about those societies, besides pointy ears.