Air circulation and condensation in custom enclosures for outdoor project
Vents do not prevent condensation. Condensation is prevented by keeping he temperature inside the enclosure above the dew point. The only way to do that is to keep the temperature inside of the box higher than the temperature outside the box. To some extent that will happen naturally for any box that contains something that generates heat. Everything that uses electrical power generates heat.

You need to determine how much heat is generated inside each box.

You need to determine the maximum safe operating temperature for each item in each box.

You need to determine how much box surface area is required to dissipate the internal heat at the temperature differential between inside and outside that is tolerable.

If the boxes are exposed to the sun, you need to calculate the heat gained by each box due to the sun.

You need to determine if there will be a problematic temperature difference between areas in each box. If that is a problem, a fan may be needed to circulate air in the box.

You may need to design each box individually according to what is inside.