Completely different color in Library and Develop (calibration not working)

One thing to do is to set up Lightroom Classic to try to mimic your in camera settings. This works for most Nikon and Canon and many Sony cameras. In Preferences, go to presets and in the top popup (global), select "camera settings". This will automatically select a camera matching profile and attempt to read any in-camera settings and mimic those. This will only apply to new imports but for already imported images, try to select the "camera settings" preset which is present in the defaults section in the presets sidebar. This will have the same effect.

How did you calibrate your monitor?

What is the type of your monitor?

If it is a wide gamut type, you need to calibrate it with a hardware calibration device like a Spyder or alike.

The reason why you see this difference is because you imported the images with 'Embedded & sidecar' selected as option for the previews. That means that the Lightroom library module will show you the embedded previews that the camera generated, and did not yet generate previews of its own. But these are edited previews and edited in different software (the camera software), so they won't match with what Lightroom does. When you open the image in the develop module, Lightroom will generate a preview based on its own raw engine. This image has not yet been exited, so that increases the difference. Once you've made edits, the library and the develop module should match, because then the library previews get updated to what you did in Lightroom.