On top of it, they have lied about testing. https://i.imgur.com/woNxPhx.jpg
Yeah, no. Pretty sure that's just a rando with GrapheneOS logo as their avatar. The way they talk doesn't sound like the dev to me, and I also don't think the dev would ever misspell a word like "cellular" as "cullar".
Can you please give a link to this guide? Thanks.