Unfortunately the only way to achieve this is to customize using APIs and programming.
The API endpoint, getOrganizationDevicesBootsHistory (GET /organizations/{organizationId}/devices/boots/history), returns a list of all boot records for devices in the organization. If a device is currently online, you can use these records to derive uptime by subtracting the current time with the bootedAt timestamp. You can use API endpoint getOrganizationDevicesBootsHistory, providing the history of your device boots, and getOrganizationDevicesAvailabilitiesChangeHistory, providing the change history of your device availabilities, together for a more complete view.
I am not a Cisco Meraki employee. My suggestions are based on documentation of Meraki best practices and day-to-day experience.
Please, if this post was useful, leave your kudos and mark it as solved.