The main requirement is to use React, with which the Forminer's components are written. In addition, TypeScript and Sass are also used, if your current application already uses both you're good to go. If not, you may need to configure your bundler (e.g. Webpack, Parcel, etc.) to handle such files. Bundler configuration is fairly easy process. Another option is to transpile (translate) all of the code manually, before incorporating it into your project.
If you're using another frontend framework it's not all lost! In any major frontend framework like Angular, Vue, Svelte, Ember, and many more there is a possibility to install React. After doing that next step would be to check React documentation on how to implement it correctly in your app - Integrating with Other View Libraries.
One of real life examples: you can create a simple React-based app (e.g. with Create React App) that will be used by forms creators, and use an application built with Angular for your customers that uses React and render the proper forms within it.
Yes, as per the explanation above
What are possible workarounds for other technologies? What is not possible at all?
If you are able to install and use React with your current project then it's possible to use Forminer. Please also check the dependencies section of technical documentation.