Google has an algorithm that assesses the mobile-friendliness of websites, and it's possible that your website didn't meet their criteria for mobile-friendliness. The issues you mentioned, such as text being too small and content being wider than the screen, can be problematic for mobile users and may result in a poor user experience.
To ensure that your website is mobile-friendly, you can use Google's Mobile-Friendly Test tool, which will analyze your website and provide suggestions for improvement. You can also use the Mobile Usability report in Google Search Console to identify any mobile usability issues on your website.
In terms of the specific issues you mentioned, you can try adjusting the font size to make it more legible on smaller screens, ensuring that your content fits within the width of the screen, and making sure that buttons and other interactive elements are large enough and spaced out properly for easy use on a mobile device.
If you need to know more about React, Its recommended to join React JS Online Course today.