If you create your private key yourself, using my method of pressing the keyboard many times, typing absolutely random letters and numbers, and then encrypting your randomly typed phrase into the private key SHA-256, you will be sure that the private key The key is created from a strong phrase that can not be cracked. If I'm wrong, correct me.
Your randomly typed phrase does not look very random. You have only letters in it. Where are all the /&%")?#@*^Ä- characters? A good random string is a string that cannot be compressed. Your string can be compressed, because it uses only a part of all characters.
However. Even if that is not truly random, I believe no-one could crack your key currently. Just make your "random" string longer. You can give SHA256 algorithm much longer strings.
You can change one or two characters in your private key, put a small amount of bitcoins on the changed private key, and keep all your balance in a private key about when you only know one or two characters that you need to change in your private key in order to access your main Bitcoins. In the event that your private key is stolen, the attacker will receive a small part of bitcoins,
That is a brilliant idea, I have never heard before
nice layer of extra security.