You can replicate those light levels indoors, if you're bloody minded enough to do so. It's somewhat expensive but for a tech-enabled crowd not too difficult.

You need about 10x to 100x the lighting most people are satisfied with indoors, and you need to turn it on whenever you're in the room and leave it on between sunrise and sunset. This is easiest with timers and automation.

The most important thing about all of this is to realize that children NEED outdoor recess sometime between the hours of 10am and 2pm every day. They don't have to be directly exposed to the sun, but they need to be in an environment with >1000 lux, more is generally better, for a number of hours. This will prevent their growing eyes from continuing to grow indefinitely.

We know this because there was an intervention in Taiwan, which has extremely high myopia levels in children (80%+ last I heard), and it dropped myopia from ~80% to ~35% in the intervention group. That's an astounding effectiveness for something free.