Mycelium needs no light. Fruiting does. DMR gives oyster pinheads 200 lux for 8 to 12 hours a day, and notes that under 100 lux caps go pale yellow. TNAU gives milky 2,500 to 3,000 lux. Shiitake incubation and fruiting use 500 to 1,000 lux. For button no Indian primary source gives a figure, so do not copy one: measure and note what works.
The crop is your best sensor. Long stem and small cap means CO2. Pale colour means low light. Cracked dry caps mean low RH. Sticky brown spots mean water lay on the cap too long. No pinheads after the switch usually means the temperature drop or fresh air never happened.