Your candidates aren't fresh out of school or just starting their careers. They already have plenty of work experience. They already know how to code and have been doing it for years. A conversation will tell you much more about their approaches to problems solving, team work, and mentoring than a coding challenge will. Looking at their GitHub, their work experience and references will tell you the rest.
It's like asking a doctor to go over basic human anatomy.
Through all of the technical interviews I've run on behalf of multiple companies, I've become convinced that our industry is full of imposters. A terrifying number of people who are employed as developers cannot code, beyond making tiny edits to existing code, or slinging StackOverflow answers and AI generated content around. They cannot think for themselves. They rely heavily on their coworkers to make any substantial progress. If anything, modern AIs have made these people more difficult to spot. I've found these imposters within the companies I've worked for too, and if it's not possible to move them to a non-technical role where they can be productive, then it's best to fire them. If that isn't possible, then keep them out of the way of any critical work, but know that they'll continue to be a drag on their team, and will decrease the moral of those on their team who have to keep covering for them.
Once I even worked on a team (as a junior) where only 3 members out of ~16 even knew the language that was exclusively used for the job. The remaining team members accomplished nothing every day. Those stand-up meetings were painful. Drawn out to 45+ minutes of standing in a circle while the unproductive team members found new ways to explain why they haven't made progress. Then I'd see them return to their desks, and not even open their IDEs for weeks at a time. They seemed to keep their jobs because their boss didn't want to fire them, and it cost him nothing personally to keep them around, offering them a sort of corporate welfare. Perhaps having such a large team even helped him politically, but it's unclear if he cared about that since he also spent almost all of his time slacking off, playing games in the break room, while the 3 productive team members carried the rest of the team.
It’s also interesting to think about how managers could be supported better. If your old boss had been more engaged, perhaps they could’ve restructured the team or helped those who were falling behind find roles that suited their strengths better. Have you ever seen a company handle this type of situation well, or is this kind of dysfunction just too common?
I'm telling you from my own experience that this is observably not true. Twice now I've been burned by internal hires who objectively had years of experience (easy to verify when they have been working within my division) and yet couldn't code their way out of a paper bag.
And tangentially, with some of the health care experiences I've had I very well might try to administer a basic anatomy quiz to potential doctors if I thought I could get away with it.
Having hired many developers over multiple decades, let me assure you that you should definitely make sure they can actually code. Do definitely have those conversations, too, but trust me when I say that a technical conversation, a degree and several listed years of experience as a software developer on a resume are not enough to guarantee that they can actually code.