Trust me when I say I've talked to plenty of candidates who I thought were great only to learn they couldn't actually code fizzbuzz. Talking to candidates doesn't work.
You want programmers to do tricks and silly initiation dances which is your whole problem. If you actually asked real questions about their experience then you’d get a good grounding. I might do silly problems for a high profile employer but that’s likely not you. In which case if I tell you to stop wasting my time and walk out of your attempted initiation ritual then you won’t like it.
You might not be good at judging candidates. A good cto uses their gut and experience. An inexperienced or someone who doesn't have the gut uses tricks. Where do you fit?
Have you taken any courses or worked with professionals to help you with this?
There are people who genuinely believe they are good at their job, when they're not. They're not bullshitting and the conversation is genuine.
Just 10 minutes of coding (or attempting to), tells you they can't code. A little longer can tell you roughly how good they are.
Experienced developers who can code have had the misfortune of working with people who couldn't pass this, and may appreciate that the members of their new team can.