When I open rich-text files created in OS X's/macOS's TextEdit on Windows in WordPad or Microsoft Word, neither bulleted/unordered lists' nor numbered/lettered/ordered lists' formatting transfer over as having been read correctly. (To be more specific, this happens at least in documents where your ordered list items' delimiters have custom suffixed punctuation.) Furthermore, any attempt to add new items to such lists from within either of the latter two programs mangles their containing file's list formatting. In both cases, the result is that lists' bullets, numbers, and letters start out with proper indentation in TextEdit, then end up left-justified after going through a Windows text editor like those listed while the list item text they denote retains its earlier, correct horizontal alignment. Are there any Windows RTF editors, preferably free to download, that don't cause this problem?
FreeOffice TextMaker supports read/write of
docx. Sometime they played with limitation to
docxsaving. Version of 2016 works fine and very fast, new versions works too. Just try, it is not free, it is limited freeware.
LibreOffice/OpenOffice Writer is too big weight for your tasks, I agree. It is mainly for
MS WordPad had become too buggy with
rtfafter 8-10 Windows changes games. Btw, RTF abandoned in 2008.
AbiWord is good, but it has some bugs.
WPS Office (KingSoft Office) is by speed between MS Office and FreeOffice. Supports
You can see small comparison here https://en.wikipedia.org/wiki/Comparison_of_word_processors#Import_or_open_capabilities . The answer is not based on that wiki, but maybe it helps you.
Personally I prefer
docx format, which are more portable and supported.