building that reputation is harder than it sounds. you don't always work in positions where you have contact to other people that could build up your reputation. i was a contractor for a small company for 10 years. i had little contact with the employees in that company, only working with the boss. the boss was nice but he had no useful contacts into the industry. the employees that i did have contact with were to low in the hierarchy that they could provide meaningful connections even after they changed jobs.

how am i supposed to build up a reputation with that?

Yeah, I worked at a tiny company (<10 employees total) for five years, then was in a small company with a tiny dev team (3 engineers and 1 PM at peak) for almost five years. Now I've been at a government contractor for five years, so I have a ton of contacts now... but they tend to remain in the civic tech space, and I'd like to move into research. Where I know absolutely nobody. I feel ya.