SEO Guide: Can I Have One Brand with Multi Domains?

Hi, I have a company name "X". The client wants to create 5 different domains to rank the brand "X" with certain organic keywords.

The content are unique, just the structure are the same.

We tried this and didn't see any result.

Is this HURT our SEO?
Thanks.

For the same KW, there is some kind of limit. I saw it in 2018