When it comes to shapewear, it seems that the more it is comfortable, the less it actually does its job. I got a waist clincher from the dollar store recently, and it did nothing. This is because it was too thin to possibly re-shape my waist. So if you want results, you will have to go with something that is thick and strong, or something with boning. Thankfully, boning is now made of materials that can flex, and so it can still be comfortable.
Here are two example I found – I like the black one but you have to make sure it won’t show through what you are wearing:
Shapewear with boning pictured:
Left: Squeem Firm Compression Miracle Vest Shapewear, beige
Right: 8 Of Hearts Waist Firm Compression Waist Cincher Shapewear Bustier Body Shaper, black