Hello.

The BITSAT is an entrance exam that provides a gateway for students to apply for bits across the country. COMEDK UGET is an entrance exam that allows students to across the country to apply for colleges in Karnataka. The difficulty level of BITSAT is higher than COMEDK usually, as BITSAT has English and logical reasoning whereas COMEDK has only PCM(b). You could refer several books used for Jee  preparations along with NCERT for COMEDK. For BITSAT, you could use the BITSAT explorer to assist you in English and logical reasoning.

Hope this helps.