I feel like a 5-minute conversation, not a pre-determined list of oral questions, on most non-hard science topics would be enough to evaluate a student. You could even have an LLM grade it as a second opinion.
Not the LLM part though.
Not only do you get a good sense of what they know, but you get a chance to give real individual feedback about what they need to focus on next.
Of course towards the end in order to get a qualification that a university will accept as entrance we will need to teach the kids to pass the standardised tests too.