First my measurements... which seem pretty subjective

Snug Underbust:

43.5 inches

Tight Underbust:

39 inches

Standing Bust:

46.5 inches

Leaning Bust:

47 inches

Lying Bust:

46.5 inches

I'm looking for a sports bra I can wear to start exercising comfortably again (usually HIIT on a treadmill) because I definitely get enough bouncing to be pretty uncomfortable. I also would prefer it if it was something I could get a few of and also wear in day to day life for nipple coverage - I have pasties but I feel like there's no way those can sustain daily use. I'm only 5 months in to HRT so buying a normal bra seems a waste of money since I'm sure there'll be more growth. My understanding is sports bras can be pretty flexible so there could be something with room to grow in that accomplishes what I need now, but that might be naive?

I was really hoping to get something that was just acceptable quality - fits right, doesn't look weird under clothes, etc. - in stores for like $10 or something and tried on quite a bit a few days ago. Firmly an XXL/1x in most sports bra sizing, maybe even a 2x would be more comfortable, but the lack of variety in shops I went to made those impossible to find those to try. I have yet to go to something like Lane Bryant or Torrid, because those are way more expensive than I was hoping for, but I'm willing to muster the courage to go for another round of in person research (I don't really pass and have some unease with it still).

I thought I'd order stuff on Amazon but a lot of larger sized sports bras are sized like normal bras from what I can see, hence a measurement check here.

Using the calculator it gives me 42D/DD, but following the trans guide it suggests I should be more like a 44C instead if I read it right.

Anyone have any recommendations for possibly a good fit on amazon for me, what I should be looking for or what my next step should be? I'm finally in a place I can start exercising regularly again with work and I want to get on it, but the lack of a bra is holding me back.