Maybe its changed, but when I used to use my regular address it would take around a week for delivery. The earliest any preorder ever shipped was Monday morning but it was usually Monday night when it shipped & the earliest I ever got a delivery was the Friday following Monday's release. That was when they used An Post, the 8 or so orders that they used Asendia with could take upwards of a fortnight.
I got a trial for Amazon prime a year or so ago, noticed that I could get free Release Day delivery for a UK address & tried that out. Sure enough, it shipped on Sunday, delivered to Parcel Motel on Monday & was with me Tuesday morning. Another preorder I'd made before the trial hadn't even shipped by the time my prime order arrived. Signed up for Prime straight away & have been utilising release day delivery on every order I've made since. I've even had some orders ship on the Friday before release & drop in to my parcel motel collection point late Saturday night.
Majority of my Amazon UK orders get dispatched on a Saturday or Sunday with delivery on Tuesday
I have the odd order not dispatched until Monday and very rare occasions not till Tue/Wed
But it's still delivered within 2 days after dispatch if An Post is used
Are you using your Eircode in your address
I don't use amazon prime never have
Amazon UK no longer use Asendia for Rep of Ireland address has been that way for over a year
I went out of my way to make that happen for Rep of Ireland customers and got Amazon UK to use An post instead
Amazon Germany still use Asendia for Rep of Ireland address but not Amazon UK
All my orders I had dispatched from Amazon UK when they used An post has always been delivered within 2 days this goes back years to date
An Post service is now even better all Amazon UK orders dispatched using An Post get free tracking even if you use free shipping option on orders
Some orders might not get dispatched until Tuesday or Wednesday but it still delivered within 2 working days after been dispatched
When they use An Post and late in dispatching your order some parcels shipped will be next day delivery
Sometimes Amazon UK when they are late in dispatching your pre order they use An post express post as in 1 day delivery at no extra cost
It's iParcel that can take 4-8 days