I mean, have a trial period of a week or three... That will tell you far more than a gauntlet interview process with a lot of false negatives.
Before starting my own company I was a bar raiser at Amazon. Interviews were not supposed to last weeks (though many did and there were internal metrics aimed at driving interview to offer cycle time down).
I'd much rather spend a few hours per interviewer per candidate getting a solid candidate than hiring, onboarding, training, learning the candidate is a poor fit, and ultimately going through the not-fun-for-anyone firing process.
High turnover isn't worth the lost productivity from other employees or the hit to morale. On top of that, while learning whether or not the candidate will make it through the trial, you're burning precious cash.
Learn how to interview and teach your people how to interview. It will save you heartache and money.
Especially when many of those concepts necessitate code that is less than discoverable, well documented and easy to follow?
Also, there's the cost of existing staff in interviews... if you only have 2-3 devs, and you're keeping them all in interviews with multiple candidates, you're not getting work done.