I'm so pleased to know that you tried salmon and like it! For vegetables, I eat a lot of zucchini. I used to peel the skin, then slice thick and roast in the oven, but now I can eat the skin (I'm 3 years old!) so I just slice 1/2 thick and roast with extra virgin olive oil. I think the olive oil helps smooth things, if you know what I mean! If not using e.v. olive oil, then use avocado oil. Other oils might be modified and might cause problems. Go as natural as you can, whole foods as much as possible. The pulpy soft flesh of zucchini is good for soluable fiber.
I also eat spinach. I wilt huge bunches of it in simmering broth until soft. I don't eat any vegetables raw. I also eat a lot of cauliflower and broccoli, steamed or microwaved until soft but still crunchy. You might have to try it well cooked until you figure out how crunchy you can digest. I don't know why, but I've always been able to digest cauliflower and broccoli, since day one! I buy it frozen in big bags (Costco, or grocery store), it keeps forever, and I always have it available so no excuses. A cup (or 3) of frozen broccoli, a tablespoon of water, pop them in the microwave 2 - 3 minutes and done. Also roasted cherry tomatoes with garlic and e.v. olive oil. If you make salmon and zucchini, try making it as a "sheet pan supper." Fast and easy, one pan to wash. Let us know how you manage!