LO is indeed portable across platforms but there are subtle differences in implementation (amongst others, it must integrate smoothly with the OS, its UI widget collection, the window API, …). Sometimes these differences surface in daily usage, e.g. Ctrl key is replaced with ⌘ under MacOS.
Also my answer tried to find a solution outside LO because it is not possible internally.
From my quick web interrogation, I suggested tesseract because it is available on several platforms. There is a Mac port. Additionally, you can select the text language as it seems there are add-ons to improve text recognition when language is known.
From experience, double spacing is suppressed in comments. This looks like a voluntary feature of the engine (not a configuration option). To force extra space before a paragraph, type “<br>” at start of it.