Ramen is terrible for you, but only 4 meals a week of anything is definitely not healthy either and unsustainable. I’d suggest searching on YouTube, there’s tons of videos about eating healthy (plus with some variety) on a budget!
IMO, if it’s only for a month, do your best to meet your kcal needs even if it’s not by the most nutrient dense meals. Like someone else said, look for food banks in your area. Rice, dried beans, and eggs are good, cheap staples. There might also be community centers or churches near you that will serve a plate of food to anyone who needs it, no questions asked.
I would say just get a huge bag of the rice instead of the ramen, its a little more versatile and probably about the same price per calorie. Nutritional needs are very important over the long-term, but your body can store many nutrients pretty well. Calorie needs are more important in terms of keeping your body running normally for things like work and/or school. We can burn our own fat for energy but its not a very efficient process and you’ll notice changes in energy and mood faster from a very low calorie diet than from inadequate nutritional intake. And I know there are a lot of people here who are super into fasting or very low calorie diets, and claim that they’re energizing, but that has not been my experience.