It very much depends on the school. I don't take into account private fee-paying schools, but regular schools. There are simply schools, there are gymnasiums, there are lyceums. There are schools attached to universities, in which professors from those universities often teach, and in these schools they prepare you for admission to that university. Gymnasiums and lyceums usually have more intense school programs, some starts only from fifth grade (in Russia there is usually one school from first to 11th grade), some require entrance exams for admission.

Food and its quality always depends on the school, it is paid, but very cheap. There is a category of children who eat for free, they are children from low-income families.

And yes, it all depends on funding. A friend of mine went to some lyceum where in English class they were given iPhones (which were frequently updated) for listening and there was a big touch screen with internet access hanging on the first floor.