I don't have GrapheneOS, sorry.
I tested with two Android phones, Firefox, Brave, Chrome and iOS with Safari and all were able to login with NAK, Amber, and able to create new sets of keys.
What browser are you using with GrapheneOS?
Can't wait to try it out. but there seems to be an issue. The site won't load I'm graphineOS pixel6a 
I don't have GrapheneOS, sorry.
I tested with two Android phones, Firefox, Brave, Chrome and iOS with Safari and all were able to login with NAK, Amber, and able to create new sets of keys.
What browser are you using with GrapheneOS?
