i used to have the same problem, as far as the whole 30 goes I would say lots of fat and lots of vegetables. But for your actual issue I took a probiotic for like two months and I havent really had any issues since, its been like two years now.
I'm not saying that the canola oil people are behind this but I think there are more than a few large companies who are being hurt financially by our new obsession with coconut oil.
Everyone loves a good conspiracy theory...
what sauces did you try and what didnt you like about them? There's a lot of different kinds, maybe we can find some you would like.
Are you eating at the upper end of the meal template for each meal, and including pre- and post-workout meals on days you work out? There are tips in this article: https://whole30.com/2013/12/keeping-weight-whole30/ but it really boils down to, eat more, and specifically more calorie dense options like starchy vegetables and fats. For fats, avocado, mayo, olives, coconut in any form, occasionally nuts and seeds, compliant bacon sometimes if you can find it, and oils. You can also choose fattier cuts of meat, so salmon instead of tuna, skin-on chicken.
Opt for cooked vegetables over raw most of the time, just because you can eat a greater volume of them. If you have salads, add denser vegetables to them, like beets or other roasted root vegetables, or have them along with your salad. Have potatoes, root vegetables, winter squashes, pumpkin, jicama.