This can also have the meaning “What do they mean by all this?” meaning <Are they serious??>:
— Management has decided that because of your low productivity, you won’t be getting a Christmas bonus this year.
— What are they talking about?? I sold more units that Tommy, Dave and Nick put together, and they’re all getting bonuses. This is obviously personal!

??

That's what I meant by " с дополнительным восклицательным знаком ".
Don't know about English, but in Russian, I think, you can see "??" mainly in informal conversations. "?!" is more common.

But the ?? can also be added if two or more people are talking and you’re curious as to what they’re talking about. So there are two interpretations: (1) people actually talking; (2) questioning people’s decisions/actions — and they can both take ??

Я могу ошибаться, но я всегда бы предпочел "?!"
Они это (что,) серьезно?!

А в английском разве нет "?!" ?

Вот, когда его спрашивают, он сидит и не жужжит))

I really don’t see any difference between ?? and ?! — I used them both indiscriminately. I’m more concerned with the two meanings here and how to express them in Russian. Now I see: Они это (что,) серьезно??/?! 👍🏼

Валерий, тебе больше нечем заняться?

Что за глупый вопрос? Я не могу ничего спросить что ли?

Они это (что,) серьезно??/?!

That's it