There are hundreds of cool bars for mid week where you can go, some of them: Festival, Sheldon, Florería Atlantico (informal ones); Ponyline at hotel Four seasons, Skybar at hotel Pulitzer, The Steve Bar (a bit more elegant); or Nicky Harrison, Victoria Brown, Uptown, Bradley, (those are hidden bars).
Thanks so much for the suggestions. Unfortunately I couldn’t hit everything but checked out many spots and all were great! Really helped make out time in BA amazing