Or you can just given them a way to bypass all of that, and ask them about any significant project that the candidate did build (which is relevant to the job description, open or closed source that is released) or even open source contributions towards widely used and significant projects. (Not hello world, or demo projects, or README changes.)

Both scenarios are easily verifiable (can check that you released the project or if you made that commit or not) and in the case of open-source, the interviewer can lookup at how you code-review with others, and how you respond and reason about the code review comments of others all in public to see if you actually understand the patches you or another person submitted.

A conversation can be started around it and eliminates 95% of frauds. If the candidate cannot answer this, then no choice but give a leetcode / hackerrank hard challenge and interview them again to explain their solution and why.

A net positive to everyone and all it takes to qualify is to build something that you can point to or contribute to a significant open source project. Unlike Hackerrank which has now become a negative sum race to the bottom quest with rampant cheating thanks to LLMs.

After that, a simple whiteboard challenge and that is it.