When using Yaru-dark theme, cursor is invisible in Gedit.
The same Yaru-dark in Arch Linux with Gnome 3.34 below. The theme works correctly in Gedit too and the cursor is blinking in white. (You can’t see it in the screeny, though)
In Ubuntu Yaru-dark is not consistent across apps as seen below.
You can see how snap Chromium appears in Yaru-dark here.