What are Maggi noodles and what's a good bulk substitute?

Instant ramen noodles are regular noodles that have been pre-cooked, then dried. That's likely not something you'd be able to do easily at home. It would take hours to dry them. When you add boiling water it's really only required in order to rehydrate them. You're not actually cooking them.

You could instead just get regular dried Japanese ramen noodles (or even Chinese egg noodles) and cook them. These only take about 4 or 5 minutes. They're available in most Asian supermarkets and usually come in individual portions inside a larger pack, sometimes in 4, 6, or 8 portions. They don't usually come with a flavouring mix/pack. You'd have to make that yourself.

Once your noodles are cooked, you'd need some kind of broth/sauce to put them in. Just adding raw garam masala on its own to the cooking water won't make a curry flavour. It will taste absolutely horrible - trust me, I've tried that back in the day when I was totally clueless about cooking!

A minimal curry has more than just garam masala in it. Curry is generally made by first gently frying onion, garlic, ginger and spices such as garam masala and chili powder to make a paste, before adding some liquid, such as a broth, and thickeners, etc.

If you are not up for creating a curry sauce/broth from scratch, you can buy pre-pared curry paste/sauce mixes. You'll likely also need to add some buillon/stock cube to give it enough flavour if you want a curry flavoured broth.

Obviously, all of this will involve more effort and time than just opening a pack of instant ramen. But it would certainly be more economical in the long run, save on packaging, and ultimately it could potentially taste much better if you put enough effort into making the broth, plus you get to control the ingredients, such as how much sodium/salt you put in it.

Most noodles will cook by soaking in boiling water, despite the instructions.

You'll need to experiment with the quickest cooking noodles you can buy. I suggest you do this where you do have access to cooking facilities, as if they don't soften in boiling water you'll need to finish cooking them to avoid wasting them.

Some very similar noodles to the Maggi instant ones say they should be simmered for a couple of minutes or microwaved. They don't need to be, but can be soaked in boiling water for about 4 minutes. I suggest a close-fitting lid and insulation (when lightweight camping I use them with a lidded bowl and wrap that in a towel or my warm hat).

The fine egg noodles I can buy ("simmer for 4 minutes") will just about cook that way, but take long enough that they cool down. A quick burst of heat when they're nearly done sorts that out. If you don't have access to a microwave or stove, draining the hot water off and replacing it with a little freshly-boiled water should be enough. These wholewheat noodles give both methods, but I haven't tried them (simmer, or soak in boiling water for 4 minutes).

As for flavouring, you might need to toast the spices (in bulk, in advance, then seal tightly). Some of the flavours in garam masala really want heat to develop them, and hotter than boiling water.

The Maggi noodles I get are a little salty for my tastes, so I'd happily halve the salt to try. If it's specifically sodium that's the issue, you have the choice of using reduced-sodium salt in addition to using less of it. As Rumtscho says in the comments, they probably have MSG in them. You could use a little soy sauce and/or yeast extract

Some companies will pack ramen so that there are multiple per packet (4,6,8, etc), but they don't tend to be produced locally.

So you can start running into trade-offs between how much packaging there is vs. how far it had to be shipped to get to you. And if you're ordering online, that adds even more packaging, so you're probably better off trying to find an international grocery store in your area and looking to see what brands they might offer.

Two such brands that I can get are "Ching's Secret" and "Smith & Jones", which are both manufactured in India (and may be from the same food conglomerate, from what wikipedia says). And make sure to look through the whole store -- sometimes they're not in with the other brands of ramen, because they're packaged differently.