I tried to create a plugin for Wordpress in React, I saw several tutorials but most of them out of date. Do you know any guide or documentation which can help to build just a dummy component in React which can be used as a Wordpress plugin with a simple install?
You can create API plugin in wordpress and then use it in your react-native project. First you will need to create a plugin, for whatever data you want to share between your wordpress site and React APP. you can take a look at the link below.
https://developer.wordpress.org/plugins/intro/
and also you will need to learn about wordpress REST API, for that you can look in offical Wordpress REST API HandBook,
https://developer.wordpress.org/rest-api/
Once these things are done you can, use the api's you have created in your wordpress to communicate with your React-App, React has builtin FETCH API that can be used
https://reactnative.dev/docs/network
wordpress already has a build-in, which you can use to fetch posts, media and different things from wordpress site, and use react-native Fetch api to pull the data from your wordpress site.