As someone with a large chest, this has been the only bra that gives me the support, coverage, and good hold on jumping flanges I want without uni-boob.
https://www.amazon.com/gp/aw/d/B08RZ5M3DV?psc=1&ref=ppx_pop_mob_b_asin_title
I am the same size as you 42G/H and these are the ONLY ones that have worked for me. I got rid of all the other ones I tried (like 10 different kind based on other peoples recommendations) and now have 5 of these in rotation. I wear basically nothing else. The gray one seems more supportive than the black. Get the version where there is a triangle of cloth in the middle, the other options won’t be as supportive and won’t expand the same way to cover the full breast. I got the XXL which comes with extenders, but I honestly feel like they aren’t needed as it fits just fine around the torso without them (on both the largest and smallest hooks). I change the hooks based on how engorged I am when I put them on. I don’t know how but these lift the boobs a little and fit well enough that it doesn’t smoosh the boobs together. I actually have cleavage wearing this.
https://www.amazon.com/gp/aw/d/B08RZ5M3DV?ref=ppx_pt2_mob_b_prod_image
I feel comfortable enough to be in the black ones all day and sleep in them at night. They hold the pump flanges without giving my boob muffin top over the cup area because the flange holes sit lower. The grey ones feel supportive enough for a workout. You can change the straps and I like to wear them crossed over with an X in the back for extra support, but they are just fine in the original orientation. I keep the back of the bra hooked and pull them over my head to put them on. They don’t have much cloth to help hide the nipples, but I wear them with nipple pads and everything seems to work out ok.
In addition, I’m 13 weeks postpartum. It got better after maybe 8 weeks where my boobs kind of expected when the next pump would be, but I was on a pretty strict pumping schedule of 8 times a day and didn’t deviate. I transitioned to doing 7ppd at week 10 because it seemed like my supply regulated and just dropping one did a world of difference for my mental health. But all of this was only possible because my poster has been amazing in supporting me by washing bottles and pump sets regularly and taking care of all the night feedings when I pump in the middle of the night. Once we got a routine (minimum of 5 bottles and 4 pump sets that go in the dishwasher once in the morning and once at night, plus the baby brezza sterilizer/dryer that dries in 10 min to make sure everything is extra dry when we use them) that worked for us, everything got much better.