I lived in several places, I’ll try to give some, they’re not the most authentic, or the best by any objective measure, but are things that exemplify very well my experience. I’ve added savory and sweet entries for each, and also a movie if you want to (to compensate for the fact that I don’t know many books from most of them, so most countries are just the only book I could think of)

Argentina:

• Food (savory): If you can find them, Sandwich de miga are great, but they’re very hard to find outside of Argentina, many places say they sell them but they sell just a crustless sandwich. You might have better luck with Empanadas
• Food (sweet): I you’re okay with making them, Bombon de Avena are one of my favorite treats, and they’re very easy to make. I doubt you’ll find anywhere that sells them, though, so I’ll leave another option Alfajor
• Album: This one is difficult, I’m going to have to go with Poncho Al Viento from Soledad, but also anything from Los Chalchaleros would be great. I tried to go with Folklore because everyone knows about Tango and someone had already mentioned Sui Generis before.
• Book: La autopista del sur, it’s not particularly good but it’s the only one I could think of
• Movie: 9 Reinas, one of my favorite movies, it’s a heist movie about stealing some post stamps.

Brazil:

• Food (savory): There are many options here, I thought on going very specific with Nord eastern food, but you might have difficulty finding it. Instead I’ll go with Coixinha, I think it’s the ultimate Brazilian snack, for a full meal Brazilians prefer rice and black beans, but that’s also found in multiple other cultures, whereas the Coixinha, specially the one of Frango Catupiry, is very unique.
• Food (sweet): I’m tempted to say Brigadeiro, even though I find it extremely sweet it’s the default Brazilian sweet snack. However I’ll go with the close second Beijinho which is similar except coconut flavored instead of chocolate, and IMO much much less cloying.
• Album: uff, this is hard, I wanna say Construção by Chico Buarque, but I feel you’re likely to have been recommended it in the past. I’m going to go with a very weird choice here and recommend Transpiração Continua Prolongada from Charlie Brown Jr, it’s very different from what people think as Brazilian music and everyone who was in Brazil in the 2000s knows them.
• Book: Os Sete from Andre Vianco, most of the Brazilian books I had to read were for school and they’re old so not a good read, plus they’re social critics that if you don’t know the culture can be missed. Os sete is a Vampire story, it’s the Interview with the Vampire from Brazil. It’s not great, but it’s enjoyable.
• Movie: Tropa de elite, many people might recommend Cidade de Deus which is also very good, but I feel Tropa de Elite is better to make outsiders understand the state of things.

Ireland:

• Food (savory): Guiness Stew, although mostly a touristy dish I love it, sided with some garlic mashed potatoes it’s a great food for a good winter.
• Food (sweet): I honestly can’t think of any Irish sweets besides adding Bailey to some other sweet.
• Album: Very cliche, but when I think of Ireland the first thing that pops to mind is The Dubliners.
• Book: I’m gonna go with Dracula, if you haven’t read it give it a go, try to forget he’s a vampire, as that makes the book a lot more enjoyable.
• Movie: Drawing a blank here too, but since you didn’t asked for movies and this is an extra category I thought the rest was worth including.

I skipped Italy as I wouldn’t have book recommendation and whichever food I was going to recommend it’s likely you have had it or are not able to. Similarly for Spain plus the added juggling of whether to recommend Spanish or Catalan things.