Thank you for your question. While the application of the criteria for halal and haram music is upon the muqallid, that does not mean that the criteria itself is completely subjective. There are some genres of music as well as songs that are clearly impermissible. At the same time, there are other genres of music and songs that are clearly permissible. But the judgement of thr muqallid is more of a factor in the grey areas, where if one person consider the criteria to apply to a specific piece of music making it haram, whereas another person may find it halal using the same criteria. It is worth mentioning that the rulings of the Maraja and the criteria they have set for halal and haram music also varies and so it is possible for a piece of music to be halal according to one criteria and haram according to another.
May you always be successful