I love how chabad imagines itself immune to criticism because it situated itself all over the world.
Living in places without a frum community is itself questionable. It does nothing to legitimize a movement, even if frum people avail themselves of those resources when necessary.
I regard stam Lubavitch wine as stam yeinom, given the amount of people who pray to their rebbe and/or ascribe any sort of divinity to him. Same with shechitah.
I personally would only daven in chabad shuls where i know the rov and the people who daven there do not have these issues. Otherwise I’d rather daven beyechidus, because davening to a rebbe is not davening, and such people wouldn’t count for a minyan regardless.
If the only issue they have is messianism, that would not disqualify them for anything, but i have a hard time imagining a messianic who doesn’t believe in atzmus-guf ideology or praying to their rebbe. But if such people exist, I’d eat their meat and drink their wine, and daven with them while holding my nose at their narrishkeit.