It had already been like this long before widespread LLM adoption: quality hiring was only really possible through manual candidate scouting on LinkedIn, at conferences, through word of mouth, and so on.
Sending a CV had already become mostly useless 3–4 years ago because of the huge amount of noise: candidates applying from all over the world, often even spoofing their actual location, FAANGs firing, flooding the market with (in theory) great candidates with great resumes.
The solution is the same one that has been successfully used forever: a trial period.
Luckily, a video interview with a senior developer is still enough to spot a good candidate.
Go through real code: add a bug to a branch of your codebase, have the candidate share their screen on TeamViewer, and let them debug and fix the issue. Ask questions live to understand how they reason about the system, how they would test whether the change works, and so on.
This will filter out 99% of candidates. But it is still possible to get lucky, which is why the trial period matters.
I’ve never had major issues and have always hired very strong engineers. I only had to terminate someone after the trial period twice.