As long as you updated to 3.5.5 Stable before, you should be good to go.

Just clone your drive and you are good to go.

Unless you messed with the partition table to add a Windows partition, SteamOS will automatically expand your home partition to the full size of the disk on bootup.

SteamOS does that automatically. You don’t need to do that manually.

It’s still present in ⚙️ Settings › Display › Adjust Display Colors

There’s also a new toggle Use Native Color Temperature under Advanced

Direct source: https://github.com/ValveSoftware/gamescope/blob/05407167cd843ddb59f71d3209d7f8751e526ae5/src/drm.cpp#L906