If LR didn't support the camera, you wouldn't be able to import raw files from it. The problem with the "missing profile" is that Adobe currently is not creating camera-matching profiles for Canon cameras that produce raw files in the CR3 format (the EOS R was an exception, as that uses the same sensor as the 5D MkIV, so Adobe are able to re-use the same camera matching profiles that are used on the 5DIV's CR2 raws). It's been a long time now, and still no sign of camera matching profiles for CR3 raw files, so there's clearly an issue somewhere between Adobe and Canon.
The usual Adobe raw profiles should still be available, of course.