Regarding safety.
Assuming you would live in nicer neighborhood in CABA or a nice town in Regional Argentina:
For those coming from "safe" places or bubbles like North America there can indeed be
moments of frustration when one realizes they need to think twice about doing something / going somewhere / trusting someone etc. However, I cannot say it is so bad that it creates paranoia, unlike living in the nicer parts of Rio or Bogotá, for example. Perhaps this would be different if one lived in a house in the suburbs outside of a gated community or a "less desirable" area.
Living in nice neighborhoods in CABA you rarely need to go to a less nice neighborhood. You make your bubble where you live. In the nicer neighborhoods, there is good police presence and a lot of movement on the street. You don't really see or feel crime in air, but would you leave your phone sitting on a sidewalk café table, tote a Prada bag around your should or leave said bag sitting on the front seat of your car? No way in hell. To be honest I see and feel less petty crime on the streets of Palermo and Microcentro than in Barcelona where every week (at least) I would see a grab and go robbery and myself having suffered a few lost phones. You can get a better feel for reported crimes in different neighborhoods here:
https://mapa.seguridadciudad.gob.ar/
Fortunately, my only "crime" incident here to date was the robbery of all of my possessions inside my apartment at the time. A blanket. You, see when I got my apartment I spent a few weeks having painting and refurb etc done. I had a blanket in the living room that I would use to sit on while waiting for tradesmen to arrive etc. One day after being away for a week I discovered it had gone. One of those m*******s stole my blanket!
That said crime here does traditionally increase when the economic situation is bad. There is a real fear amongst many locals about people who sneak into buildings or accompany occupants from outside at gunpoint to rob apartments. Apparently it has even happened in my building twice in the past during the bad years around 2002/3 (right next to the US embassy residence..) and there have been a few cases on the news in Recoletta lately of criminals going in through the garage. Given the current deepening crisis, it is likely we will see a few years of relative insecurity again where incidents in nicer areas become more commonplace.
Regarding general peace of mind. Forget it. Things change 20 times in a week usually without anyone telling you. It is incredibly frustrating and time-consuming to get
anything done. This includes both getting money and spending it. The quality of work and goods (construction, appliances, furniture, etc.) is
generally terrible meaning you are always paying to get things fixed or replaced. Complaining achieves very little here. There are fewer options for anything you want than in the outside world and prices can be crazy expensive for some things that you would not expect, while other things can be far cheaper than you would have ever imagined. You will either accept this inconsistent reality and find a way to deal with things or end up having a nervous breakdown and retreating to wherever you came from with some serious mental trauma.
Aside from the downers above, there is little else likely to ruin your experience down here as a retiree. The rest is actually quite OK (assuming you view local politics as a spectator sport!)