If you already deleted the files in macOS, use Lightroom’s Synchronize command on the affected folder (or higher-level folder if needed). Lightroom can detect the missing files and give you the option to remove them from the catalog.

You can also locate the missing photos in Lightroom and delete those catalog entries there; Lightroom will warn that the files can’t be found, and you can proceed.

For the future, the better workflow is to delete unwanted images from within Lightroom rather than in the operating system. That removes them from the catalog and also gives you the option to delete the actual files from disk, keeping both Lightroom and the filesystem in sync.