Question related to a study of rare variants

[kjaja]

I am working on a project to detect rare variants associated with a phenotype of intertest. However, I have about 200 cases and 50,000 controls samples with exome sequencing data. I am considering using the burden test to test for case enrichment of rare variants compared to controls. However, given the small sample size, I am not sure if I have enough power to detect rare variants. My question is how to calculate power? And is there a better study design that I should consider to detect rare variants associated with a phenotype given the sample sizes.
Any help is greatly appreciated,