If you get this to work well for you, tell us how.
I’ve used it on pages of Greek that I’ve typed and found problems.
First, I figured out that I needed to convert everything from Basic to Extended (or is it from Extended to Basic). But the extension includes a tool that does that nicely with a click.
Then I found that the spellchecker worked nicely for nearly all words, but certain words that are marked as spelled wrong though they are not. I wonder if it has to do with the Basic/Extended problem.
If I understand right, when the standard Greek polytonic unicode map was made, there was a misunderstanding about certain characters being different between modern and ancient greek, so they duplicated them. Somewhere I have a list of which ones were duplicated.
As I have only just upgraded my libre office, I haven’t had a chance to try out the conversion macros yet. I have noticed how multiple values will mean some correct words as errors but this isn’t too much of a problem as it will supply a correction with the form it is happy with. However I have just checked and it does seem to handle these duplicates better now.
If you find your list, do post it. I and I assume others would be curious to know what this Unicode duplication consists of.
(As a side note this is why it would be a bad idea to have an Ancient Greek password)