Hi Martin,
It can be, that's the actual answer. As React is using JavaScript to load its pages and load the content in most cases. Google and other search engines are able to read the content but it's always required in these cases to check what the actual result is. I've worked with many sites using React and it depends if they're using server or client-side rendering. Start there, to figure out what you can be using for your client/company. Some teams are really drawn to the client side rendering which is a little bit more dangerous as not always can Google see the actual content. In case of server-side rendering, I've seen it go well for most of these.
Let me know if you have any specific questions, happy to answer them!
Martijn.