Very much a novice Inkscape user although I have been using Inkscape for a few years to tidy up figures that the JMP statistical platform doesn't do well. A recent development has been that inserting text in .sf results in incorrect font sizes that no amount of fiddle with seems to rectify. This happens even if I copy/cut and paste correctly sized font into a new area on the document. Interestingly, it seems this phenomenon started occurring some time in the last year. In the attached document. I add recently created figures which exhibit this problem while the figures that were created over a year ago do not. In this example the text, nM*hr was copied and pasted from an older figure and from a newly created figure. The text from the new figure appears to be bold although the font style says it is normal. The other text which is from an older figure output is normal.

The next shot shows text simply typed in as new. Completely illegible.

I am using Inkscape 1.2.2 installed with a .exe installer on Windows 11

With regard to the new text being wonky, I'd reduce or remove the stroke from the text tool and text objects.

The other part of the question, I'll need more description of the issue and an example file to test.