In order for us to provide better support, we need to see the log generated by Citra. This guide will walk you through how you can obtain the log file: How to Upload the Log File.
you don’t met the requirements required for installing it…
The app requires a minimum of 64-bit Android 8 (Oreo), and OpenGL ES 3.2 support . These are relatively high requirements; however, they allow us to ensure that every device that can run Citra will have a reasonably good experience. As for hardware, we recommend a device with a Snapdragon 835 or better.
You phone might not be supporting it, because it requires a much powerful processor. It’s minimum requirements are snapdragon 665. Try downloading it on other device. Hope it helps