So far I thought that peltir should not be used to cool down electronics as it may lead to condensation and thus damage the components.

I suppose it would depend on if you design for that. For example, this board could be coated in epoxy to remove that risk. That would be preybad for repairability though

Isn't it a general issue if you have parts that are (significantly) colder than the surrounding air, no matter the material? If you turn on the peltir element and it reaches a temperature of X degrees on the cold side and the air around it has a temperature of X + Y, the air is chilled by Y and will thereby lower its ability to retain the moisture and form little droplets on the surface. The higher Y and the higher the relative moisture, the higher the effect.