Hhmm, I thought I had quick reply open for everyone by default, but I'll investigate. You should at least see a text link, maybe with a plus sign in front of it. (+ "Quick Reply" in the dark blue bar, under the dropdown menu "Jump to:" with "go" button) (Although if you've disabled animation globally, it's probably not triggering your symptoms to see the full editor. I don't think many people use it anymore, but the forum software allows animation to be disabled by individual members.)
Yes, one thing that annoys me about GIMP is those stupid marching ants (the selection indicator). You can slow them down, but they won't stop. I'm sure other programs use it too. I have a slight issue with flashing things, but not nearly as severe as you, apparently.
If you can use Inkscape from the command line and/or.....well I was going to say shell mode, but I don't entirely understand what that is, and I have a nagging feeling that's only for Windows. But the command line would avoid the canvas competely, as far as I understand. I'm afraid I don't know how to use it, but here's a reference:
https://inkscape.org/en/doc/inkscape-man.html As a Mac user, you're possibly already somewhat familiar with it?
That blinking text cursor must be built in to almost every program or app which uses text - just guessing. I can only imagine what a chore this must be, to track down a program which doesn't use it (or allows it to be disabled). I know in Windows you can configure the speed of the blink, but I don't remember whether it can be completely disabled.
Oh, does the size of the cursor matter? If it's smaller, does that make it more tolerable? If so, you could use Inkscape's Text and Font dialog. It's the large T icon on the command bar. (All of Inkscape's text features used to be accessed from there. Now, most of the features are available on the canvas, so most people don't need to open it. But if being smaller helps, this might be a good solution for you.
It has 3 tabs. The first one, Font, only displays the text which is already typed, I guess so you can see the size. But you can also choose the font and set the size there. There's no cursor there, but on the other hand, it doesn't look like text can be entered there.
The 2nd tab is Text. It's a very basic editor, where you can enter text, highlight, cut, copy, paste, and check your spelling. As far as I can tell, the text is always approx 8 or 10 pt or px (I can't keep the units straight) no matter what size you set it for the canvas. So even though that cursor blinks, it's fairly small.
The 3rd tab has a bunch of new features which I don't understand yet, but I don't think they would help you.
Anyway, this dialog is so large, you could use it to cover up the canvas while you have the Text tool enabled. That would block you from seeing the cursor. And then, always make sure to switch back to the Selection tool, before you move the dialog off the canvas.
Or else, as I said before, use the command line.
