Considering that "sentience" has enough "philosophical leeway" that it's just as reasonable to assert that LLMs are sentient (and at extremes, that they have been sentient for years) -- especially if we are, as you suggest, supposed to include any philosophically possible definition -- I don't think that's a meaningful rebuttal. If no one can agree on whether it's sentient, it's bad faith to choose a fringe definition that hands off its definition to such a nebulous term.

In fact, I'd argue that statements about what "is" and "is not" sentient relies on even more spirituality and word games for anything that isn't a terran tetrapod.

For a meaningful -- "helpful" -- discussion on such things, one has to assume that everyone is choosing a definition which is closer to the median usage and relies on not being totally subjective. Furthermore, given the breadth of options, it should be assumed to be a definition which allows which permits the form of the question to be meaningful, rather than begging the question -- if your definition is tautological enough that non-biological entities can't have understanding, you're just expressing dogma rather than having a discussion.

Anything else is bad faith, or assuming bad faith on the part of the participants.