I mean, like… To which Manjaro fuckup are they referring?

Obviously, I’m not the author. But if I’d have to guess, their answer would likely be “Yes.”.

Not OP. But, FWIW, I’ve been daily driving secureblue for over a year now. And it has been wonderful experience.

Note that, by virtue of its superior security model, preconceived knowledge may not translate well. However, if you read its documentation and FAQ, then I’m pretty confident that you should be fine. Thankfully, if something’s not clear or if you’re facing issues, then you’re in good hands through their Discord.