I went in Dec 22 and we had a great time (albeit not with kids).
We did 4 days in rio then iguazu and ilha grande.
Rio- We were sensible with valuables (leaving at least one credit card and new phones in safe in hotel). Took out an old phone to take pics. Our hotel, on copacabana, had it's own section so we got chairs near the bar and the people that looked after it kept a watchful eye over things. We got Ubers which were dirt cheap and we used the metro (dead easy using contactless). In the evening we went out and about for dinner, no problems whatsoever. The only place that felt sketchy to me was the steps.
We did sugar loaf, ctr, favela tour, stadium, the little tram ride to the top of the arty district, beach, shopping malls (rainy day and fancied a Starbucks). I absolutely loved it.
Iguazu and ilha grande were perfectly safe with very few precautions taken.
The caveat to all this is that I am quite an experienced traveller and have quite a confident air about me (been to places with bad reputations before) and my other half could pass for Brazilian if he kept his mouth shut so maybe we were left alone.
I would go if I were you 😄. Enjoy!