I reckon that a lot of blame lies with An Post. They are not capable of dealing with the logistics industry as it is today, not capable of training their staff, not capable of dealing with changes, and are generally still living in the eighties.
As an anecdote, shipping from Ireland to Las Canarias was suspended in March 2020 due to Coronavirus. Shipping resumed three months later when we came out of lockdown and the flights started arriving. (Yes, we've been out of lockdown since June 2020).
However, since then, the An Post website says that no shipping is available to Las Canarias. Yet if you walk into an actual An Post office, and they will send the stuff down here no problem.
That's a year and a half that their website is out of date, and they have been contacted numerous times by various senders. If they can't get something that simple correct, how on earth will they survive BrExit, customs, VAT etc???