What's the best knowledge base / help center product for small startups

I want to have something similar to this https://help.descript.com/en/

Of course, there's Intercom, Zendesk, and many other companies providing such product. But they all bundle together a lot of tools that I don't need, thus their products are a bit pricey for a small startup.

Ideally, there's a knowledge base / help center SaaS under $20/month, and it supports custom domain (e.g., help.mycompany.com) and looks similar to https://help.descript.com/en/ :)