Which of the two is the better option - pursuing CS after completing B.Com or M.Com

Its better if you can concurrently plan CS Course and do M Com at the same time. Remember, MCom is a university post graduation degree, neither an equivalent nor a professional membership. But if you have no plans to do M Com you can also proceed with CS alone. To broaden your prospects in the job m

You can directly start doing your CS, without further delay. An M.COM is not going to give you any value addition.