[deng]

I tried the exact same thing a few weeks ago with a de-googled phone and it did not work. I had to transfer the /data/data/com.whatsapp folder as well via root access, then it restored the chats (the display of the old phone was dead and hence I couldn't initiate any kind of account transfer to a new phone).

[wolvoleo]

Weird, for me it worked fine. I didn't need to transfer the root parts. Nor did I do anything else on the old phone. I just signed in on the new one with the backups in place.

I don't use Google services or an account either, though I do have Google play installed.