When hiring juniors hunger to learn should far outweigh qualifications and raw knowledge in a particular technology imo.
That said, I think there may be a deeper issue here. You want to hire seniors which suggests that your startup _needs_ seniors and the experience that they bring. But you're hiring juniors.
You're going to end up disappointed as you need senior developers at this point.
They're going to end up disappointed as they require senior developers in the team to learn from and grow.
(Perhaps unrelated, I think if you've interviewed 400 people and haven't found someone "good enough", the issue may not be with the candidates...)
That said, I think there may be a deeper issue here. You want to hire seniors which suggests that your startup _needs_ seniors and the experience that they bring. But you're hiring juniors.
You're going to end up disappointed as you need senior developers at this point.
They're going to end up disappointed as they require senior developers in the team to learn from and grow.
(Perhaps unrelated, I think if you've interviewed 400 people and haven't found someone "good enough", the issue may not be with the candidates...)