I’m not sure I’ve heard the term ‘self discipline’ used except in self flagellation. As in, “That’s it; I HAVE to develop SELF DISCIPLINE!”
I think it’s much more productive to focus on building good habits. You have lots and lots of them already.
You pay your mortgage, you get enough sleep, you keep your house maintained. Presumably you attend to some form of personal hygiene before work. These are all great habits that you have developed over years.
Habits can be built. Depending on what you read, it takes between 30 and 90 days to develop a good habit. Why not pick one thing this week that will make a 50% difference in your life and focus on developing it into a habit.