Can anyone British or Irish explain what the EU wanted to do with the Irish border during the recent vaccine contretemps?
AstraZeneca got caught red-handed exporting vaccines from Belgium to the UK, probably because the UK was either paying more, or it was in the contract with AZ that they would have first dibs on produced vaccines.
So, the EU wanted to impose customs controls on the Irish border in order to prevent trucks from exporting to the UK that way. It was a huge faux pas, because there was no need for it - they could simply check trucks arriving in Ireland at the ports and leave the Irish border alone. They very quickly went back on the idea, but there were good intentions there in terms of looking after EU citizens.
her vaccine buying program was.... a lot less optimal than the UK's,
That's largely the old West-East issue, plus political moves by France to blame. The poorer EU countries didn't want to commit to buying huge stocks of more expensive vaccines when AZ and others promised huge amounts of cheap vaccines, while the French also made some demands because they've got their own vaccine in development that they naturally want to sell instead.
I have to say that I don't think the common vaccine purchase was a good idea at all. I understand why it was done (bulk buying power and the power of negotiating as a bloc), but the amount of compromises that had to be made has resulted in this situation.