I'm really scared when I post anything that suggests that PeterNLewis was wrong, because it's usually me that's wrong, but the Title Case filter that he put in that macro doesn't decapitalize the second letter. Look closely in these conversions in the image below. The one you were worried about, which is the second one in this list, is NOT fixed by this action.
Basically the Title Case filter ignores any word that has a capital letter inside the word. So this is not what you want.
There is a second problem in his macro, which he explicitly identified. That is, you might type too fast for this macro to work all the time. He described how you might be able to fix that, but I can see you didn't make that change.
My first question for you is why are you trying to use a macro to fix this, when macOS already has a feature that fixes this, called spelling autocorrection. It specifically solves the problem, and works 100% of the time. When I type "CAnada", it fixes it automatically. You can enable this feature in System Settings, Keyboard, Input Sources, Edit, "Correct Spelling Automatically (ON)." Have you tried this feature?