IMU will tell whether you are moving and your orientation, but it won’t tell much of about your geolocation provided by the GNSS, which is what most spyware wants to track.
The Librem 5 will have software switches so you can turn off your GNSS and IMU, while still using the WiFi and/or cellular modem.
Of course, Google created a database of the range of WiFi networks and cellular towers when creating StreetView, so it has the ability to track your geolocation through the WiFi and/or cellular modem, even when the GNSS is turned off. If you have an app installed which uses Google’s Geolocation API, then Google can collect your geolocation data even if your GNSS is turned off. That is why it is best to stick to apps whose creators don’t have a business model based on monetizing people’s personal data.