What is the Tablet Tester showing when you draw on the grid area?
I don’t know the XP Pen tablets at all but this post shows someone who does:
@screwdycrow may be able to give more advice about this.
I’ve changed the title of your post to get the attention of other people who use the same tablet.
You can try: disconnect tablet, uninstall tablet driver, full power down restart, reinstall tablet driver, full power down restart, connect tablet.
Then try again with Wintab at the krita side and with Windows Ink disabled in the tablet utility.