I feel your pain on sodium; anything convenient always has absurd amounts. One suggestion is street tacos with low-sodium tortillas (for me usually corn, though storebought suck and are bitter if not steamed immediately before serving) if you are willing to prep the toppings in advance. Lunch the day of is about as much effort as assembling a sandwich: reheat toppings on tortillas, and then add freshness (e.g., cilantro, citrus juice, raw onion). Chopped onions and lemons last maybe a week in the fridge but lose a bit of their pungency.

For prep, I add a bit of oil and black pepper to chopped veggies like bell peppers, hot peppers, onions, garlic, or corn and char broil the lot in the oven. I also usually presoak 1 cup of black beans and then blast them in my instant pot for 1 h with 2.5-3 cups water, half an onion, a couple cloves of garlic cut in half, and a bayleaf or two (don't bother chopping anything, remove before serving). Then, I add 3 oz tomato paste and mexican-adjacent seasonings and simmer until it thickens up. I like this premade salt-free spice blend, but I ran out recently and am using 1 tsp cumin, 1.5 tsp ancho chili powder, 0.5 tsp each of smoked paprika and hot chili powder, and < 0.25 tsp salt. The same mixes go well on e.g., chicken breast prepped however you like if you also want meat on your tacos.

If you're looking for ways to cut sodium but are annoyed by blandness, I've found that smokey things like paprika and the char on the veggies can go a long way toward compensating for reduced salt. Nutritional yeast is also maybe 70% of the way there umami-wise to high-sodium cheeses like parmesan.

Also also, if you are reducing sodium for blood pressure reasons, and if you are not on ACE inhibitors, salt cut with potassium chloride ("low-sodium salt") can help, as can foods rich in potassium like tomatoes and beans. If you are on ACE inhibitors, check with your doc; they make your body retain potassium and can cause problems if you eat to much of K.

Sorry for the long post, it's 01:00 and my rambling got the better of me.

Soups and stews are great for meal prep. They're also great for weight loss because they have a high water content adding bulk without calories. They are also usually easy to make in a slow cooker.

https://ifoodreal.com/slow-cooker-vegetarian-lentil-soup/