I've added:
QTextBlockFormatH : needed for paragraphs alignments (such as paragraph indents, line spacing and tabs). QTextEdit only exposes paragraph alignment.
QTextCharFormatH : needed for additional character formatting (i.e. vertical alignment, links support). QTextEdit only exposes font styles.
Some others too, but someone must implement it into richtext component (qt5 and qt6 widgetsets). I don't have enough spare time to do that...