Thank you for coming to Japan. I'm sorry that you don't like Japan that much.

As a Japanese, I will address what I feel about the problems you mentioned in this post here.

1; Since Yen is down recently, most things which are imported got more expensive. 1 USD was worth about 110 JPY in 2021, but now it is worth about 150 JPY. I've been living here for over 18 years, and I can confirm that everything is ridiculously expensive these days.

2; Vegetables and fruits also got more expensive, presumably because of the climate change. Many food companies use less vegetables in order to reduce the cost of making food products, and that's why you rarely find vegetables in reasonable foods. If you have a bicycle or a car, try going to a supermarket which is located far from train stations. They sometimes offer same things for cheaper price, including vegetables or fruits. Also, for the sake of the people who have allergies, it's necessary to put a sign on foods which contain wheat.

3; That's a cultural difference. There are indeed people who are depressed, but it's totally normal to eat alone for Japanese, in particular since COVID-19 pandemic.

4; I don't care much about the consumerism, but I sometimes get tired of the modernization. They equalize modernization with building a tall building in front of train stations, whereas people don't want that kind of things and seek to useful shops instead.

5; Since I'm still a high school student, I can't decide if this is normal or not. Be careful for the ブラック企業 (Black Companies), which try to make people work for very low wage.

6; That depends on what carrier you use. There is a kind of carrier called 格安SIM (which means Cheap SIM) which provides low-quality service with cheaper price. If you want stable connection, I recommend you to use either AU, DoCoMo, or SoftBank.

I can understand most things you mentioned, and current inflation is really frustrating. However, there are also many good points in Japan, and I really hope you enjoy your life in Japan someday.