Not surprisingly, Hannan tries to rewrite history. He says that the UK and Ireland were quietly working out a border deal until the EU intervened after the 2017 election which returned a "remain majority" and emboldened the EU to use NI to undercut Brexit. https://www.telegraph.co.uk/news/2021/02/06/hypocritical-brussels-can-no-longer-claim-right-meddle-northern/
There is a baseless Brexiteer myth that Enda Kenny was being constructive but all changed with the arrival of Varadaker. There is no evidence for this. But for Brexiteers like Hannan all the problems of Brexit, including those involving NI, are someone else's fault.
A much more astute take on NI is to be found from the Observer's @NickCohen4 who underscores the complete and utter miscalculations of the DUP since 2018 over Brexit. They now find themselves without political friends or political leverage. https://www.theguardian.com/commentisfree/2021/feb/06/ireland-conservatives-dup-union-brexit
With UK business already hurting from Brexit, even with the EU/UK TCA in place, would any UK gov be unwise enough to put the TCA at risk by tearing up the Protocol to satisfy the DUP and some ultras? Remember the TCA has still to be approved by the EP. https://www.theguardian.com/politics/2021/feb/06/fury-at-gove-as-exports-to-eu-slashed-by-68-since-brexit
As @DenisMacShane has long identified, Brexiternity will see the UK negotiating with the EU forever and a day. Big issues around finance, data transfers, for example, still remain to be resolved. Tearing up the Protocol will destroy any negotiating capital the UK has with the EU.
The mistake that Brexiteers like Hannan make is this. The EU has all the infrastructure, processes and procedures in place through the CU/SM to facilitate trade with third countries. The UK is struggling to build such an infrastructure for EU trade. It will not happen quickly.
While it works to build the infrastructure, how much worse would things be if the TCA collapsed because the UK scrapped the Protocol at the demand of the DUP. You got to see the big picture. But then, seeing the big picture was never a DUP strength.