I like https://www.appsmith.com/ which provides front end as a service for publishing internal tools.

The good thing about appsmith is it comes with self-hosted version. For data-conscious companies, it's the perfect solution.

Developers can collaboratively build internal tools and publish them.

The vast library of UI components on appsmith gives you enough flexibility to build the apps the way you want them with simple drag and drops.

You can build your internal apps by connecting APIs as well as databases. I personally like the API support as it gives me control over input validations and flexibility to add business logic as well.