To be perfectly honest, I just started eating meat again after being a vegetarian for 13 years. Long term it wasn't the healthiest choice for me as I was eating too many carbs (healthy carbs like lentils and beans and whole grains - not junk food carbs) and not getting enough protein. Over time, the diet was a recipe for weight gain, hormonal imbalance, and sluggishness. The challenge is that vegetarian meals are often combinations of carbs (like rice and beans) so even if they're healthy carbs, it still too many servings of carbs at one time. Since I started eating meat again, and aiming for 4-5 oz of meat for lunch and dinner, and limiting my carbs to 3/4c or 35g per carby item, I've been surprised to find that I'm so much more satisfied and feel so much better than I would after a vegetarian meal with too many servings of healthy carbs.
That said, I would recommend a couple of things:
I've been working with a nutritionist since last fall to learn how to eat since adding meat back in. One of templates I use for constructing a meal is to have a combination of protein, fat, fiber and greens at every meal. When I'm getting a good balance of all those things, I'm satiated and well fueled until the next meal. So no, cauliflower steaks on their own is not a meal. Most vegetarian meals at restaurants are total fails, often completely lacking a protein. You won't be satisfied if you aren't eating enough protein, and if you're cutting back on meat proteins at your other meals, you family's hunger may stem from long term protein deficiencies.
- We eat a ton of chickpeas, which are wonderfully flexible - a can of sauteed chickpeas is a delicious snack. To make a meal of them we'd add an assortment of veggies (kale, sauteed zucchini, sauteed cauliflower rice, etc) with avocado and feta. Chickpeas also can be added to many soups and fit in harmoniously. I have tried every canned chickpea on the market - Goya tastes best.
- Other beans: We buy Rancho Gordo heirloom beans which are as easy to cook as simmering a pot of beans over with half an onion, a couple cloves of garlic and a peeled carrot and a very generous pour of good olive oil (like 1/4c+). We'd start the simmering in the morning and they're ready for dinner. You can also use a crockpot or instapot if you plan to leave the house or want them ready in less time. The Rancho Gordo beans are crucial - heirloom beans are just so much more delicious than the mainstream beans (black beans, kidney beans, chickpeas, etc) available at the grocery store. They're expensive per bag compared to other beans but a 1lb bag can easily serve an entire family so overall it's actually a relatively cheap meal. We'd serve the beans over brown rice and with kale sauteed with lots of garlic. Rancho Gordo has a cookbook and frankly, not a single recipe is bad. We love the lentil soup and the bean pot pie in particular.
- Speaking of lentils, black and green lentils are more delicious and versatile than green lentils which, in my opinion, are super bland no matter what. A really good lentil soup is chef's kiss. Red lentils, which largely dissolve, are great additions to other foods - adds proteins and can increase satiety. We'd add red lentils to our vegetarian chili to make it super hearty. Can also be added to other soups and they disintegrate and fully absorb the flavor of the soup. You can use black or green lentils in much the same way you'd use ground beef. Lentil tacos, made with taco seasoning was a favorite of ours.
- A lot of egg dishes like quiche, frittata (cook's illustrated instructions for frittata are perfect), scrambled eggs, hardboiled eggs (as snacks, in salads), etc. But I'd find that I'd need at least 3 eggs in a serving to feel satisfied.
- Consider adding protein powder to meals. I will add it to lower protein soups. I also make smoothies with protein powder using my fat fiber protein greens formula - usually plain greek yogurt, protein powder, chia seeds, pysillium husk (fiber), 1/2-2/3rd banana, electrolyte tablet (important for the flavor), and a cup or two of whatever green leafy veg I have on hand. It's not sweet, protein packed, incredibly satiating and easy to put together in 5 minutes. I've used vanilla greek yogurt in the past instead of adding the electrolyte tablet, but I swapped it because my nutritionist has a 4g sugar cap and the vanilla yogurt had 9g of sugar. Though protein powder is expensive - if preparing a family meal, I'd honestly rather have a meat on the side.
I was excited when the fake meats like beyond and impossible meats came out, but ultimately decided against included them in my diet. They're ultraprocessed foods and in the long run likely aren't going to prove to be good for our health.
Frankly, a lot of vegetarian diets lack adequate protein. The amount of protein in proper serving of beans just can't compare to the amount of protein in meat, and once you increase the serving to get enough protein, you're overeating carbs. If you all are mindful about empty carbs, you may also want to pay attention to overeating carbs too. I didn't like tofu but it really is one of the best vegetarian proteins in terms of being higher protein and lower carb. You might want to keep eating it - I kept eating tofu and eventually came to like it. Tofu continues to be one of my staple proteins even as I'm eating meat again. Low carb and very versatile in how you can prepare it and it can be included in a lot of different cuisines. Andrew Weil has a tofu kimchi soup that is on regular rotation in my house.
You may need to reconsider/lower your fish standards. Buying salmon and other fish in bulk from Costco can be more affordable but I don't know if their fish meets your standards.