That’s a misunderstanding of what an observer is. An observer is better thought of as an interaction which distinguishes between states; there need not be a conscious observer. For example, long wavelength light interacting with the electrons in the double slit experiment does not affect the interference pattern because long wavelength light interacts with both states of the superposition in the same way. Short wavelength light has different physical characteristics than long wavelength light and interacts with one state of the superposition differently than the other, resulting in decoherence and the wave function “collapsing”.

There are other problems with the Copenhagen Interpretation, but this isn’t one of them