Not sure if others have had this same issue. When I upload my photos from my camera to my laptop, the colors are perfect, just what I shot. When I import them into LR Classic, it changes the colors dramatically. I was just using it a couple of weeks ago with no issues, and now all of a suddent it's doing this. I was getting Support help last night for over 3 hours and still hasn't resolved the issue. Waiting to hear from Support again today. Just wanted to see if others out there have had this issue and what fixed the problem!
It's expected that the preview of raws will update/change after import because Lightroom Classic has to build its own proprietary previews from the raw. Could that be what you are seeing? Is it possible you're importing and using some import preset that has edits being applied? We need more info, perhaps a screen capture of your Import dialog and preferences>presets dialog.
Author “Color Management for Photographers" & "Photoshop CC Color Management" (pluralsight.com)
If you have a supported camera (mostly Canon, Nikon, and Sony), change the default for that camera in Preferences->Settings to "camera settings" . This will make Classic attempt to recreate the proprietary to the camera maker rendering. upon import. On already imported files try to apply the "camera settings" preset.