There is homework, but Finland has both less homework and less hours spend in school compared to other countries, but the quality of teaching is better. Teachers are better educated and motivated.

Especially for little kids, more hours in school does not increase learning. Sleeping later in the morning is better.

Having nutritious school lunches (for free) probably plays a role too. Kids' may hate the food, but it's not junk like pizza, juice and jam.

As a person who was put through the Finnish schoolsystem, I can say that homework definitely exists in Finland. However, it greatly depends on the specific school and teachers. Some give little homework while others give substantial amounts. The average time I spent was probably about 45 minutes, and my peers did less. In the high school I attended much homework was given but I only rarely did any of it, and got excellent grades anyway. That is to say, generally speaking homework has no religious status in Finland, but the details depend on the teachers.

And school is indeed quite relaxed in Finland. Bullying does exist though, but there is absolutely none of this elite school racing mentality where you have to attend the right kindergarten, do many goal-oriented extracurricular activities and basically prove your exceptionality almost daily.