An endpoint computing device multi-network slice remediation/productivity system includes a core network system coupled to a RAN system and configured to allocate network slices and make them available for use in wireless communications via the RAN system. While operating in a pre-boot environment, an endpoint computing device determines that it is unable to transition to operating in a runtime environment and, in response, establishes a remediation network connection with a first network slice, and establishes a productivity network connection with a second network slice. While operating in a pre-boot environment and performing the remediation operations, the endpoint computing device then performs remediation operations via remediation wireless communications over the remediation network connection with the first network slice, and provides access to productivity application(s) that are configured to allow a user to perform productivity operations via productivity wireless communications over the productivity network connection with the second network slice.