The UK signed the Northern Ireland Agreement to help the south with its membership of the EU via the UK. But Article 16 was written to deal with issues if the amendment caused difficulties in the north.
Unfortunately, the EU has been so heavy-handed it has caused exactly the issues that we feared.
So Article 16 looks likely to be triggered.
Now the EU whines. And Ireland complains to Biden who has no business getting involved. But the EU [and Ireland with it] has brought it on itself. Unlike them, we tried to be benign.