So I was doing step by step what is in the video, and when I changed in Platforms - Windows → Targeted RHIs → Default RHI to Vulkan and Restarted the project as it asked, it was constantly crashing and I could get back into the project.
I had to go to the project folder/Config/DefaultEngine.ini find the DefaultGraphicsRHI and change it back to DefaultGraphicsRHI_DX12.
I don’t know if my PC is so problematic or if changing to Vulkan should be said with some caveats.
So this is just a manual for people who would encounter the same problem as I did.