What is the best way to store chopped vegetables?

I'm a fan of prepping some vegetables for the week on a day off. I'm much more likely to eat salad if I have the fixings ready in my fridge. I'm no expert, this is just what I've found works best for me.

Certainly some vegetables are more suited to cutting and storing than others. I find controlling humidity and condensation in storage to be the most important factor. I store almost everything in covered pyrex, unless it needs to breath (and those go in the humid compartment). Veggies with less water can be kept humid with a lightly moist paper towel on top. Wetter veggies can cause condensation and lead to sliminess. A dry paper towel and/or an open container can help with that. A veggie should either be submerged in water, or not in water at all. Sitting in condensation is that biggest problem in storage.

Cut carrots keep in water for a week with no change in quality. Out of water, they can dry out a bit. I don't find the dryness to be a problem.

Sliced bell peppers keep pretty well with a moist paper towel in the container.

I find onions to be pretty indestructible, though the flavor gets a bit milder over time.

Broccoli and cauliflower are also pretty hardy. A dry paper towel or two will deal with water from washing them, which is the biggest problem I've had.

Mushrooms and leafy greens need to breath.

Cucumbers and tomatoes don't store as well as others.

Do you really want to do this? The vegetable will loose water, it will loose juice and part of its sabor. Especially in the fridge, where the air is more dry. You could use special compartments in some fridges which solve this problem and tend to keep moisture (some expensive fridges have it) so that the food is not dried. I wouldn't recommend freezing at all.

Anyway, the surface of vegetable pieces will tighten and become dry. Even if there is still water inside the pieces, the tightened surface will not allow to release its taste during cooking as with freshly chopped vegetable.

If you know you gonna use all your veggies in the week don't use the fridge but a freezer at -4°C chop the veggies, store in boxes, done. to defrost for a salad, stir a bit with the sauce you want always fresh and tasty

I would try to refrain from doing this as much as possible, but if time saving is needed then when I am short of time during a certain day, the night before when I'm making a cuppa or supper in the kitcehn, while waiting for the kettle or the toaster I quickly chop them up then. If you do it 24hours earlier they don't lose too much taste or moisture. Potatoes are my hated one, so i peel and chop and leave in a pan of water. You can refrigerate but we have a small fridge and leaving then out for a day brings no harm, just make sure to rinse again before cooking. I find uncovered for veg is always best, so they can breathe. I don't like preping tomatoes and cucumber early as they lose their firmness, become mushy and lose taste. The best I find for preping early is brocili, cabbage, cauliflower, and carrots, turnip and butternut squash kept in water. Onions and mushrooms are usually fine left uncovered but things like celery and peppers I prefer to chop fresh.