To recommend a replacement for connector J1 in your ICM-20648 IMU reference design, we need to consider the following:

Given these requirements, a suitable replacement for J1 would be a 4-pin header connector that supports I2C communication standards and can accommodate the power supply voltage and current requirements for your IMU sensor. Typically, these are available in both male and female variants, depending on your design's needs.

Remember, the specific part chosen must match your PCB layout footprint (if already designed) or you may have to adjust the footprint to match the chosen part. It should also be compatible with the other connector (if applicable) and suitable for the operating environment of your device (e.g., temperature, mechanical stress).

Please verify the exact specifications needed for your application, including the required current rating and any mechanical constraints, before making a final decision.