Lighting planning - mixture of spots, strips, and lamps

A conversion from lumen to lux does not work that simply, even though it is often simplified that way on the internet, because we are dealing with luminaires that do not radiate omnidirectionally but rather in a directed manner, have reflectors, baffles, lenses, diffusers, and whatever else. The values give the layperson a false sense of security. Don’t forget your own experience when choosing the luminaires. Light and illuminated objects can be seen, that helps.

A conversion from lumen to lux is not that simple, even though it is often simplified like that on the internet

I am fully aware of that, and my knowledge is not based on any info sites on the internet, but the difference between the simplified calculation and the measured values still seems too large to me. And especially with directional lights, the calculation is actually rather closer to reality than further away. ;) However, the specified lumens can of course be very optimistically chosen, and not everyone has an integrating sphere at home to verify that.