@Gaetano, You’ve already reported this in two other topics:
Krita text editor bugs, version 5.2.3
and The text editor changes the default font with each Krita update
I’ve merged this latest report into your main previous report.
The developer responsible for the text tool has been made aware of this.
Please do not report this again.
If you find anything additional (not related to fonts, such as the sub/superscript) problem that you reported then by all means make an additional topic for the subject.
I’ve changed the category of this topic.