Hi there,
So I just got one of these in the DHL ? I swear I compiled the Arduino LSM example and flashed it and I was getting some data, then It went Failed to Initialize IMU
I tried the other 5 LSM6DS3 LIBs and got nowhere fast. YMMV
I was able to load and connect with the BLE_Blinky example from the IDE, be sure to select SIL_BLE instead of Matter,Arduino_BLE or NONE I used NRF_desktop and the Nordic dongle to scan and connect and flip the LED on/OFF AOK
Sleep examples work also.
HTH
GL 
PJ 
The I2C address 0x6A is the same as the IMU in the Nrf52840 Sense device with IMU, BTW…