My husband and I went down this path as I saw a woman with a similar build at a hotel pool with a very cute bikini and I could not help but ask where she got it. I grew up in a very rich area and was the only thick girl surrounded by Gwyneth Paltrow clones.
I need support for DD boobs and am size 16-18. My best bet has been string thong bottoms, the fixed band type tend to be very inflexible and the tie sides work way better.
My husband has a spreadsheet and bless him he is the most body positive person I know
Thank God for Amazon,. I would highly recommend you order from Amazon or places with a liberal return policy as we just frequently order a large amount and then have to return all of them or just find the right fit and return so I can ge the right color.
Here are my go to brands, many don't have say thong but the style is essentially a thong or extemely cheeky when you wedge it like most bottoms are now.
Body Glove - Smoothies Brasilia side tie bottom, Kalea bottom up to XL. My go to fave. I also recommend the regular tie bottom if you need something for when MIL is around :)
Tainehs (Amazon brand) thong bikini bottom up to XXL, so many color options
Swimsuits for all - Camille Kostek classic string bikini
Shein has this rare gem up to 4XL but 0XL worked for me, it a cheap but colorful option. searching on their site is near impossible and this is the only Shein bikini I have
https://us.shein.com/Plus-Triangle-Tie-Side-Bikini-Swimsuit-p-6982237-cat-1941.html
Mapale thong set 1X-3X https://www.amazon.com/Mapale-6728X-Bikini/dp/B09QH4ZC3J?th=1
Bandeau version also, doesn't work for me because I need straps for support
https://sohotswimwear.com/products/black-side-strap-adjustable-coverage-top-bottom-bikini-plus-size?\_pos=29&\_sid=6fb198afa&\_ss=r&variant=3958056766678
These next one border is probably the more risqué but it does fit
YandY - Thong String bikini bottom, they don't market it as plus but XL fits great, the top is too small but the colors are easy too blend with other brands
Good luck!!!!!
P. S. I also found a one piece thong suit that works if you need it. My biggest issue finding one is that one piece thong suits have zero support for boobs and and tend to be open under the arms or on the sides. It took nearly two years to find something with that has no open side or back.
They are weird Chinese ones and can take weeks to get the color I wanted. I had to order 3X to fit me but it goes up to 5x!
https://www.amazon.com/gp/product/B09TQKRT84/ref=ppx\_yo\_dt\_b\_search\_asin\_title?ie=UTF8&th=1