Rex mine has been operating or two years now.
While there is condensation that forms overnight very easily on the outside of the observatory I haven’t had any problem because of the panels with respect to dew. I’m sure some must form on the inside but it dries off quickly enough.
My observatory is quite a bit larger so has more air generally inside. It’s about 8m x 11m.
The only auction I would mention with your plan is if you house heat generating equipment inside the observatory and the insulation keeps that heat in. Computers and associated equipment can generate a surprising amount of heat when in a well insulated box and so that heat can actually get trapped and cause more problems than the heat that the insulation is keeping out of the observatory
More applicable for small spaces.
Regards,
Roger.