The Znamya project already tried this and it’s a 100-year old idea at least.

The Znamya 2 was a 20-metre wide space solar mirror. […] when illuminated, produced a 5 km wide bright spot, which traversed Europe from southern France to western Russia at a speed of 8 km/s. The bright spot had a luminosity equivalent to approximately that of a full moon.[3] Although clouds covered much of Europe that morning, a few ground observers reported seeing a flash of light as the beam swept by.

For reference: the Sun is about 400’000x brighter than the Moon.

It’s just tech-bros pumping stocks with space-slop and sci-fi hopium.