Empirically, Final Fantasy 14. Also my only 1000 hour game since games services started logging playtimes in a more durable way. Only other games I can think that might have touched that time are Diablo II and UT99, but both of those playtimes are lost to the sands of time.
When I recently upgraded my phone I was surprised how little got brought over automatically and how hard it was to migrate configurations. If it actually copies over all my preferences from old phone to new phone, then great. If it’s just logins then that’s not really useful.