I’m unable to have the text appear in a decent point size. That was always the case with stuff I wrote directly at the dashboard, but stuff I used to copy from elsewhere would appear in larger characters. Now it’s all miniscule and hard to read.
I looked around but I don’t see how to have the text appear in a larger size (I also can’t imagine why the default is so small).
That’s because you have been copy-pasting from sources that carry font-type and font-size commands with them. You shouldn’t be doing that, because you may introduce all kinds of junk code. When you copy from other sources, use the “Paste as Plain Text” button of the editor. For the posts you have already published, you can get rid of those extra commands by copying the text from the visual editor and pasting it in the html editor.