Ireland is probably pushing the current deadline harder than anyone tbh. We dont want a proposal to the NI border, we want a specific solution to it. There wont be a better chance to force it than now. If the other 27 are prepared to continue negotiations despite the lack of agreement on NI, then were under a lot of pressure to go along with it. So ... yeah.
Germany would benefit from allowing it but ... I think they'll back Ireland up, their government is pretty pro EU. At least as long a fair majority of other governments weren't in support.
I'm sure theres plenty of anti EU governments knocking about Europe that could be convinced.