Hi Thomas, thanks for your question!
I understand during interview, subjectivity and biases might be an important concern. Those factors might be impacted by organization's culture, needs, or even specific personality requirements during job opening.
So far we have come to several solutions on how to give fairer and better opportunities to everyone (and to judge right/wrong, good/bad), by creating a tangible qualifications of each level (junior 1, junior 2, medior 1, medior 2, etc.) so we would know whether the candidate has fulfilled our requirements.
More than that, usually there will be more than 1 stage of interview, to see different aspects of each candidate. Portfolio review might help us see the candidate's experience, fit interview might help us see whether candidate can work with different stakeholders, white-boarding interview might help us see candidate's problem solving & critical thinking skills. These interview stages will also be handled by different interviewer and different stakeholders to avoid biases & subjectivity. What I have written might only cover small parts of the whole interview flow & stages.
I hope this answers your concern 🙂