>>>Ireland: Republic of, and Northern Ireland-of UK.
Correct. Republic of Ireland is EU, Northern Ireland is UK. So to prevent freedom of movement into the UK from the EU, you have to have controls on the border.
Quite correct, Priti Patel effectively said that she will implement SOME kind of border - it may be this spot checks and cameras - but they haven’t yet got anything like this in place.
OR they may be considering putting a border in the IRish sea between NI and the rUK — THIS would work but the DUP won’t be happy