It’s good to hear you like milk because if you do not eat meat, lentils, beans, or soy you may need to consume a lot of dairy. A relatively small amount of cheese would be sufficient since that is very nutrivtive but if milk is the only dairy you consume, you may need (depending on how tall you are and so on) as much as a liter per day (including the amount used in cooking). You probably need less and your daily egg in particular reduces your need for milk so my wild guess considering what you’re eating and so forth is that be you’d need half a liter per day.
Some veggies like cauliflower or spinach could bring that figure down when you eat large servings (uncooked cauliflower is worth about two-thirds of its volume in milk for this purpose). If you ate large cereal servings (not recommended for weight loss!), that might also bring down the figure.
Most veggies have similar benefits but some have special properties (see above). Tomatoes and zucchini help lower the acidity of your urine more than most vegetables for instance.
If you eat a lot of different vegetables, you don’t need to worry about whether this one or that one is best. Even plants you might not think of as nutritious such as coffee actually contain nutrients lacking in most other plants. So variety is the one thing most likely to provide you everything you need and I would therefore recommend all veggies.
What’s your concern about spinach by the way? Obviously if you don’t digest it well or it makes you sick, you shouldn’t force yourself to eat that.