- Edited
No other device meets the criteria to have GrapheneOS support. The closest to that will probably be with the Pixel Tablet, which is a tablet, but I don't see why it couldn't be used as laptop (much like the iPad). So I guess there's your answer.
If you're looking for something "similar" in the sense that it doesn't suck security-wise and has a closer security model than other options, your best options are probably a Chromebook or an iPad.