Never use YouTube video
tutorials. They are often outdated and/or wrong. In this case, it was probably both.
Follow one of the two guides I listed above. When you're done, you will likely have a fuse count mismatch that will prevent you from booting your Switch without the use of a custom bootloader like fusee-primary or Hekate. Once you are able to successfully boot your system with fusee-primary or Hekate, you should make a NAND backup with Hekate. Since you likely have 9 burnt fuses, you will need to then update to 7.0.0 or higher for your Switch to be able to boot normally again.
There is no reason not to update to 8.1.0. If you want to preserve your present fuse count, you can install AutoRCM.