The XT4 is on the Apple list of raw formats supported by macOS 12.4, so in theory the Mac Finder should be able to use QuickLook to preview it, if the camera is set to embed a preview into its raw files.
Are they compressed in any way? Because in that Apple list, footnote #3 for Fuji raw formats says “Uncompressed RAW format only.”
Ultimately Nancy’s right that this is more of a question to ask Apple, rather than a question about Lightroom Classic.