Google has made it increasingly easier to move from one device to another. Last time I upgraded, I was surprised how much of my settings were transferred to the new device, and how little was left for me to configure.
A little bit of background; I used to root every one of my phones just so I could do a complete backup/restore of all apps and their data when upgrading or changing ROM/OS. Switching/upgrading was a breeze. The last time I upgraded to a new device, I allowed Google to do the restore for me and (as above) it was so complete that I didn't even have to use my (rooted) backup.

My current device (Pixel 8) is on stock OS, and it's backing up to Google cloud. Now, and as I'm preparing for a move to GOS, I wonder if I would be able to restore on GOS what stock OS has backed up to Google. Does GOS have something similar to transfer-settings-from-another-device during its setup process?

P.S. At this point I take Google collecting what it does as a given and with the P8 (which is not rooted) I mostly went along with it, and initially, at least, I intend to use GOS as a 1:1 replacement for stock OS.

    MarSOnEarth My current device (Pixel 8) is on stock OS, and it's backing up to Google cloud. Now, and as I'm preparing for a move to GOS, I wonder if I would be able to restore on GOS what stock OS has backed up to Google.

    GrapheneOS does not include Google's cloud-backup transport (Google has not open-sourced it). I believe there is no way to get the Google cloud backup onto a GrapheneOS device.

    MarSOnEarth Does GOS have something similar to transfer-settings-from-another-device during its setup process?

    Yes and no. There is an app called SeedVault, which in theory could transfer apps and settings and app data between GrapheneOS devices and even between GrapheneOS devices and devices running other Android variants that ship SeedVault. However, SeedVault doesn't work very well. The GrapheneOS developers have mentioned that they want to replace it.

    Further information: https://discuss.grapheneos.org/d/15284-switching-graphene-os-phones/2

          de0u GrapheneOS does not include Google's cloud-backup transport (Google has not open-sourced it). I believe there is no way to get the Google cloud backup onto a GrapheneOS device.

          Ah! Of course... Google cloud.

            MarSOnEarth when I used Google's backup in the past, it wasn't even reliable. It only brought over a fraction of my SMS/MMS history for example. SMS Backup & Restore is superior and also allows local backups if you want to avoid uploading your SMS/MMS history to the cloud unencrypted.

            Backing up settings can be tedious, but if you're used to using multiple profiles, it's something you have to do regardless whenever you make a new one. For everything else, I just backup settings on an app-by-app basis once in awhile. A lot of privacy respecting apps have an export settings/data feature and some feature automatic backups. I keep a folder on my phone for all of my App data, with a subfolder for each App. All I need to do is give permission for the App to access its respective subfolder in order to make backups.

            You could then upload these files to a cloud service you trust (or through Cryptomator), by manually moving them to to a USB device or desktop, or sync it to another device with Syncthing.

            It takes <30 minutes for me to setup a new device this way (plus an overnight to fully restore my 15 years of SMS/MMS history).

              Thanks for chiming in. Before nandroid images, and then SwiftBackup backups, which reduced switching ROMs to minutes, it used to take me 3-4 days to fully configure a new device. Now it looks like it will be back to that at least once, although even without root, SwiftBackup can still (with Shizuku) create backup of most everything on device, except for App data. Once; and then I'll be waiting for that future and still elusive GOS backup after I switch to the OS.