Find when device was activated I am trying to figure out when my devices (tablet, tv dongle, etc) were activated. Is there a place (in google account settings, device files, anywhere) this data can be obtained?

My devices are rooted, so I can use terminal access to read internal files if needed.

Some suggestions in the net say to find the first day of data usage in the logs, but I want to find an accurate date (preferably a timestamp) of the device activation.

I can't seem t be able to type dialer codes in a tablet, there's no phone app. Also this question is about android devices in general, not only phones.
If the date of activation matches the date of adding your Google account to the device, there's an easy way to check (unless you did a factory-reset in the meantime, and had to re-add the account):


with your Google account's credentials, log in to the Google Dashboard
Scroll to the section labeled "Android" and expand it (by clicking its title / the LGM [little green man])
Check the entry for the device you want to know the date for


At this place you should find the date you registered your device. That doesn't reflect the first time a device was added, but the last time the Google account was activated on the device. So if you activate your Google account following a factory-reset, this field is updated and thus reflects this point-in-time.