Carryfast:
There is no 90 day rule between UK and Eire which supercedes EU rule.
True that a UK driver can stay and work in Eire, and that the Ei/GB CTA precedes Brexit, and continues to-day, but how does that affect a UK driver (UK passport holder) in an Irish truck working in the EU? The OP was asking about working in Europe, and although Eire is of course in Europe, I don`t think that is what he meant.