Export from macOS: Go to System Settings → Keyboard → Text Replacements. Select all (⌘A), then drag them to your Desktop. This creates a file called Text Substitutions.plist.

Import here: Drag that .plist file into the drop zone above, or click to browse for it.

Edit freely: Add, edit, delete, and search your replacements. Everything happens instantly.

Export back: Click Export .plist to download the file. Then drag it into the Text Replacements window in System Settings to import.