The only way to know if the guy who despite years of experience could not pass an interview is to hire and see. There are many with "senior" in their title who can't get the job done without inflating technical debt, etc. Probably. it was not important in their past workplaces. Maybe, nobody cared (yet).

I wish I knew the magic for finding promising juniors... I know - those exist out there.

But usually not with TODO app portfolios.