If my worship and bhajan feel meaningless, what might be the underlying issue and the solution presented in Chapter 50?

If your worship feels meaningless, Chapter 50 suggests the underlying issue is that the mind is soiled by Avidya, or ignorance. The text explicitly states that without Brahman-knowledge, bhajan and worship are meaningless. The solution proposed is to cultivate devotion to God, as the cleansing of the mind cannot happen without it. Devotion is the proof that the bondage of ignorance will be destroyed. Just as a special collyrium allows one to see hidden things, devotion allows ignorance to be removed so that true knowledge can dawn and spiritual practices can become meaningful.