No it is not. The openHABian docs do not “recommend” neither Pis nor Grafana. Remind you openHABian is not openHAB and Grafana is not part of openHAB an even in openHABian it’s just an option.
Also remind you we’re talking about the recommendation to go into NEW openHAB docs in this thread, it is not about existing docs, not about openHABian or any optional complementary software or combination of any of these.
And the Pi recommendation isn’t to cover all use cases. It’s not even a “recommendation” but a suggestion, and written for the user to try out OH for the first time.
Read the text.
I understand you’re annoyed because you understood it that way and now you have problems, but that doesn’t entitle you to go cherry-picking only those parts and interpretations of the docs that made you select this combo.
I wish @ThomDietrich hadn’t written that slogan to contain “hassle-free” long ago because ever since a lot of people with problems come along and complain “hey, but you promised no hassles” regardless of whether their problems really can be attributed to openHABian. Most cannot, and any interpretation to go like that is naive on the user part anyway.