You’ve already reported the font change in this topic here:
The text editor changes the default font with each Krita update
Sub/Superscript problems are probably more complex.
The text capabilities of krita are undergoing a major change and upgrade at the moment.
The developer who is dealing with this will be aware of the situation.
Until this is resolved, you may want to consider using your previous version of krita to maintain compatibility with your previous work using text.