A ‘question’ is not a native typst element, so we need more information about how you have set this up. Are you using some specific package? Or are you referring to a specific level of headings as a question?
A regular typst counter is independent of sections and does not reset between sections already, so that would be an option here.
Maybe you want a part and chapters structure here, then I would recommend this existing solution, the quoted part is the only part you need, just update the numbering patterns to match your desired “A” and “Q1.1”: