Your work ethic didn’t come from nowhere. Somebody showed you what showing up looks like.

Discipline feels like a personal trait, something you either have or do not. Mostly it was learned by watching, long before you could name it. Somebody got up when it was cold and dark, finished the boring part, went in when they would rather not, and did it near enough to you that it became normal. What looks like your character is partly their habit, borrowed.

Work out who that was for you, and tell them. One sentence is plenty, naming the specific thing you copied. People rarely know they taught anything, and hearing it is the sort of news that keeps.