Has a doctor specializing in trans HRT told you that T is too dangerous for your heart, or is it something you assume you can’t do because of relatives’ health issues? You don’t have to answer, I just ask because if it’s something you want then it’s worth getting an informed medical opinion over; consider that the treatment for heart issues is basically never to block T in cis men.
Feel free to disregard if you’re not interested in T regardless of the health situation, but I’d hate for you to tell yourself you can’t have it if that’s not actually the case.
Congrats on the weight loss and the upcoming surgery! My surgeon recommended Aquaphor or Vaseline for the first 6 weeks, because keeping it moist is supposed to promote minimal scarring. After that he recommended silicone scar strips, but I skipped out on those because I generally have minimal scarring when healing.
The first time I was topless in public it was intimidating, both because I’d been socialized for years to never let that happen and because I was worried people would stare at my scars. But the vast majority of people aren’t going around staring at (men’s!) chests at the beach, so that feeling went away fairly quickly and I had a good time.
Be sure to put sunscreen on your scars for at least a year when you’re topless! UV can make scarring worse, and it takes 6-12 months for everything to settle after surgery.