Like most here, I was sent home in one and given an extra by the hospital. For some extras (to wear while washing), I went by band size. I'm pretty petite around the ribs (30-32) but anticipated some swelling, bloat, and tenderness, so I bought a medium in these.

1. I had about 3-4 that I rotated through so that I could minimize laundry while recovering. I bought oversized ones from a thrift store and donated them once done. Walmart, Target, etc. also often have button-up pajama tops in the sale section.
2. Go for sweatpants or pajama bottoms for the first few days. I didn't have the upper body strength the first 2 days to yank leggings up and down.
3. -
4. My doctor had me begin walking as much as possible as soon as possible - if only to minimize risk of blood clots! I'm quite active but didn't formally work out at all during the first 6 weeks. By 1.5 weeks in I was able to walk 4-5 miles a day. This said, this is massive reconstructive surgery - you'll likely be wiped.
5. As always, big fan of this zipper-front one. Many surgeons send you home with a recovery bra that you're instructed to stick to for the first 2-4 weeks.
6. You can work the day before! I'd just lay low to avoid COVID risk and ensure your home is adequately prepped. Everything at waist high, some easy meals in the fridge, etc.
7. This Might Hurt by Stephanie Wrobel could be right up your alley. Also, watch Yellowjackets if you haven't yet!
8. COUGH DROPS. Seriously. Get good medicated ones like Cepacol. The sore throat was by far the most annoying part of the first few days for me.