Vacation with a 1,5 year old

Hello Argentinians!

I bet people are getting tired of these questions. So sorry in advance but here i go.

In september we want to go 3 weeks on vacation to Argentina. We are Belgian so we come from Belgium and land in Buenos Aires. We first want to explore Buenos Aires and then go around the country as much as is possible.

Now what better people to ask than the inhabitants of said country? What are some must do/visits? What are things we best skip and what do we need to be wary of? Is a stroller something we could use or are we better of with a walking backpack to put our child in? What national dishes do we certainly need to try? What customs are their that we need to respect?

Finally we have the weird tradition to try a mcdonalds in every country we visit. What should we get?

I already thank you all in advance and sorry for yet another trip question. But with a little kid and our first vacation abroad with her we are a bit lost.

Mods i hope this is within the rules of this subreddit.