My 2 TB SSD has 1.2TB of XMP files. How can I delete them safely?

Which version of Lightroom are you using? You've posted this question in the "Lightroom ecosystem" forum, so the assumption is that you are using the cloud-centric version which is called simply Lightroom (Lr icon). However, that version of Lightroom typically does not use or generate XMP sidecar files (though they can be produced on export if exporting proprietary raw files with the "Original + Settings" option).

The other version of Lightroom is called Lightroom Classic (LrC icon) with which all image files are stored on locally-attached hard drives. This version does have the option of generating and updating XMP sidecar files.

So, which version are you using?

Are the XMP files that you have actual sidecar files, i.e. does each individual XMP file sit alongside a proprietary raw file (both files would have the same name apart from the different file extension)?

Perhaps a screenshot of a sample of these files from File Explorer would help (include the usual details, in particular the file-size).

1.2TB of XMP files is an unbelievable number of files, given that a typical XMP sidecar file would be less than 100KB in size, so something doesn't feel right. The screenshots should help.