Does this only work on specific OSes?
you are probably seeking a method which will allow you to copy a cell(s) containing a comment(s) and paste such cell(s) in a way to keep those comments. unfortunately, such a method doesn't exist.
the only way to copy comments from a given sheet is to make a global copy of such sheet:
- go to File
- select Make a copy...
- choose Copy comments
From Create, view, or save a file (pay attention to step 4)
Make a copy of a file
- On your computer, open a Google Docs, Sheets, Slides, or Forms home screen. Open the file you want to make a copy of.
- In the menu, click File and then Make a copy.
- Type a name and choose where to save it.
- If you want to copy comments from a document, spreadsheet, or presentation, click Copy comments and suggestions or Copy comments.
- Click Ok.
The Android/ iOS apps doesn't include the option to Copy comments and suggestions / Copy comments