Using IMUs is one of the most struggling part of every Arduino lovers, here there is a simple solution.
This library will work with every IMU, it just need the raw data of gyroscope and accelerometer (the magnetometer isn't mandatory), it is based on these two libraries:
I just made small modifications in the way the libraries handled the timing between two measurements and melted them together
Use the arduino/platformIO library manager or download directly from github
Click on the video to see it on youtube
please note that the Roll is inverted
I am using an STM32F103F103 known as blue pill but also any Arduino board will work
The IMU is a cheap MPU9250, you could find it everywhere for about 2€ (eBay, Aliexpress, ecc), to use it I strongly suggest you this library
If you wish use IMU_tester in the extras folder to see how you IMU works (needs Processing)
Note: I am using also this very useful library: Streaming