So far yes, but in a situation as fluid as the current fiasco, anything may happen.
But the DUP must tread with very great care. They are a Leave party in a Remain country or province. Unionists no longer have a majority in the Assembly, which is why they are making so many difficulties about it re-opening. The majority of every class of people and business in NI support the backstop. Finally polls now confirm that if given the choice of remaining in the EU as part of a United Ireland, or exiting the EU and remaining part of the UK, the majority would go for the United Ireland.
The quickest way to fracture the UK union and make sure of a united Ireland and an independent Scotland is to force a crash Brexit. It is very unlikely in the long term that the UK as we know it can survive the Brexit trauma of the last three and a half years because of the profoundly undemocratic way in which the 2016 Referendum was organised. Forcing both NI and Scotland out against their will is domination by English nationalism that makes the union unequal to a degree which will be unacceptable without major reform of powers and governance. The now chaotic state of the UK’s constitutional structures makes that a project impossible to deliver.
The DUP. who even opposed the Good Friday Agreement, a sin for which they will find no forgiveness, now face the end of the road. Whatever happens to Brexit its days are numbered.