Will it be safe to create a private key by encrypting absolutely random letters in SHA256, for example 'sdfguhiuwrUISDHGNIUXHIUCV238778dfvhgjhuidsahgfiu', encrypt these random letters and numbers in SHA-256 and use the resulting private-key for bitcoin? I can do this with the Internet turned off, I can encrypt the absolutely randomly typed phrase 'sdfgdhfsuyghuHUDUIHGHIUG878yet7y8bchxujxcbvhidsafhguihuq' in SHA-256, write the received private key and use it to use Bitcoin? Why use some kind of generators, when you can encrypt any randomized characters typed on the keyboard, and use the resulting private-key for bitcoin? After all, in fact, no one will know the phrases with the help of which the private-key was created, and the only way to lose it is if someone other than me gets access to the private key.
Your method is good. I believe there should be 2 ways to generate keys and passwords. We are all different and someone does not want to trust the program to create keys and passwords, and someone too lazy to create their own. To simplify their creation and reduce the risk of repeated characters, there are phrase and password generators. I think it's very useful.