I'm confused in regard to the explanation below. Could anyone help me??

"We can use'could have been' to talk about possible present situations that have not happened. (Possible in Present)

eg:He could have been Prime Minister now but he got involved in a big financial scandal."
The question is, Does this sentence refer to the past or present?
Does he still have a chance to become Prime Minister? or He didn't become Prime Minister because of the scandal?

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"Could have been" is often used in situations where what you are talking about will never happen.

"We could have been movie stars." makes it sound like it will never happen.

In the example he didn't become prime minister and is not one right now because of the scandal, but it could be possible in the future.

"We could have been doing this 10 years ago" is talking about something that did not happen in the past, but Is happening right now.

Also "we could have started this project yesterday" is a sentence that still allows for the project to be started presently even using "we could have."

In general, if a specific time frame is used like "10 years ago" or "yesterday" or "now" it might still be possible in the present or future. If no specific time frame is used "we could have been" sounds like it will never happen.