Not yet. I found this article in which one of designers says “One other thing we’ll be shipping soon is the ability to do local network transfer from one Steam Deck to another, so you can transfer your library across Decks without having to re-download.” - but this doesn’t mean we’ll be able to transfer settings and custom stuff as well. And it’s not out yet.

So probably no solution for now.

Moving your SD card to new Steam Deck works - I con confirm this. But for me the question is how to clone my Steam Deck settings to a new one? I put some time in to plugins installation, emulator configuration and setting the Geforce Now / Playstation Remote solutions. It would be great to copy Steam Deck internal drive or at least configuration files in to new one.