I experienced the same behavior. As soon as I connect my Pegasus PowerBox (which has a temperature and a humidity sensor), I then have the 'Dome' tab visible in Ekos.
So I removed both sensors, booted the device, launched Ekos, and the Dome tab was still there.
So it's not the simple fact to have the sensors physically connected that triggers the Dome module but must be in the the drivers themselves somewhere. (Or something else).
It's not the connected devices that open the tabs, but loading/connecting to the driver. So you can keep them connected, but remove the driver from the profile. Removing them one at a time should tell you which one causes the dome tab to open.
Once you found the 'guilty' one check in its INDI tab if anything refers to the dome.
It's my belief that weather monitoring is part of the observatory module. If you collect weather metrics (by having weather sensors, or using weather drivers) then you will always get the observatory module visible.