"at" symbol is not working in everyplace I have connected a Microsoft keyboard to my MacBook Pro 2019. Since doing this, the @ symbol is not appearing when pressed.
Case 1:

With the integrated keyboard, in Chrome, VSCode or another text editors, or even here typing:
Key combination: right option + q: nothing happens

Case 2:

With the external keyboard, in Chrome, VSCode or another text editors, or even here typing:
Key combination: right option + q: nothing happens

Case 3:

With the integrated keyboard, Slack, Notes:
Key combination: right option + q: @ &lt;-- only that way works

Why I can't write at all the @ symbol with the external keyboard?
Why I just can write in some apps the @ symbol with the integrated keyboard?
This is the input source:

And this are the Modifier keys:
a) for integrated:

b) for external:

Note that I remapped the command/option in the USB keyboard, but with this keyboard there's no way I can write the @ symbol
If you look on your keyboard, you should see the @ above one the keys, probably the number 2. Try the combination Shift + that number and see if that works.