The problem with debates about the relationship between the UK and the EU is that they conflate, on the one hand, formal relationships between national governments -- both EU members and third parties outside the EU -- and the EU itself, which result in formal agreements and legislation, with, on the other, everything that citizens of those countries and businesses based in them do within the constraints of these agreements.
That is, most of us aren't particularly worried about what the EU or the UK or our national governments do as political institutions, except insofar as they affect us as we try to get on with our lives. The EU or the UK or any other government is relevant to this insofar as it helps us pursue our particular goals, personal or institutional, or it hinders them
Farmers or fishermen in the UK or the EU are primarily interested not in the EU or Brexit but in running viable and successful businesses, as are the hauliers who deliver their products and the shops or restaurants who buy them. Similarly, the customers of those shops and restaurants are primarily interested in what they're having for dinner tonight, not the regulatory structure involved in getting it from the sea or ground to their dinner table.
Governments are now engaged in unravelling more than 40 years' worth of regulatory practices that govern a considerable proportion of private trade and business between individuals and businesses that happen to be located in the jurisdictions of particular governments (as opposed to "British farmers" or "German exporters") and replacing them with new ones, regardless of what the individuals engaged in this particular trade or business think, and very likely against their wishes.
Regardless of which government's fault this is, it's individual citizens of particular countries who are having their lives and livelihoods disrupted by the actions of various governments, theirs or other people's, and it seems to me not unreasonable to ask governments to try to disrupt things as little as possible while doing what they think they have to.
The point that Remain supporters like me tried unsuccessfully to get across to Brexit supporters over here was that neither the EU nor the continent of Europe was going anyway if we left, and all the myriad existing relationships between individuals and businesses in the EU and the UK would either continue, or not, under a new set of rules that are being imposed by their governments, often against their own wishes and interests.
All that's happening now is that the basis of existing relationships between individuals and businesses has been disrupted by various governments as a result of Brexit, just as they have been by Covid, and the individuals and businesses are doing their best to adapt to the new environment their governments are imposing on them unasked.
People, including various customs officers and other officials, need time to get the new arrangements to work, and it seems to me only right and sensible that the governments on both sides help them adjust to the new regime in which we all find ourselves.
This is a particular problem at all the new EU-UK borders, but most particularly at the Irish border, which is the site of a particular set of long-standing historical conflicts between particular social, religious, political and criminal organisations ("Loyalist" and "Republican" areas in NI always used to be as much about who ran drugs and protection rackets in particular areas as much as anything else) that were there long before the EU and which the Irish and British governments can only attempt to manage and contain.
The NI border isn't an EU issue -- it's an historic issue between different groups on the island of Ireland which can be solved only by the Irish people on both sides of the border, with whatever assistance from outsiders (primarily the British and Irish governments) they're prepared to accept. The EU is relevant here insofar as it's part of the solution (as it was before Brexit) or part of the problem.
I remember what it was like before the Good Friday Agreement, and I also remember how "the troubles" restarted back in the late 1960s/early 1970s. The danger we could easily end up back there seems to me all too real, and if the EU won't let the Republic of Ireland and the UK set the agenda as they try to maintain the peace process, then it's likely to get very nasty again very quickly, and I really do not want to see a return to the bad old days, which is all too likely if we see what's primarily a conflict between different groups on the island of Ireland in terms of the EU vs UK.
The neat and "sensible" solution would, of course, be a united Ireland inside the EU, and it's one the UK would privately love to see, because then the north would be Dublin's problem and not ours. But since forcing the Ulster protestants into a union with the south against their will would be a very bloody and protracted process, that's not going to happen in the immediate future.
I don't know what the solution is, but the problem of the Irish border is unlike most other border problems with which the EU has to contend, and if Brussels approaches the land border between the Republic and NI in the same way it approaches the EU's other external land borders, or the channel ports, then it does a huge disservice both to one of its member states, the Republic of Ireland, and also to the people of Northern Ireland themselves.