How do you build a personal brand without being pompous cringe?

I personally admire people who don't need to be on or use social media to run their businesses. But it's become difficult to avoid not sharing something ever so often to stay relevant. People have goldfish memory spans and seem to forget things easily these days. They need reminders that xyz brand/person still exists. Plus I'm a private person and don't really like talking about myself much. And meaningful share-worthy work milestones only happen once in a while. Any good examples of people who have grown personal brands without posting occasional selfies on LinkedIn? How about outside LinkedIn? The only one that comes to my mind is Michael Burry, but I'm not nearly as good a trader as him.