How to negotiate for clinical vs protected research time in academic job offer?
It really depends on your professional goals.
if a purely clinical position is not an option for you, and if your research credentials (publications, etc) back up your ambition, then you should make that clear to the department and work with them on adapting the offer.

It is not just about salary, but would likely involve a start up package for your research, reserved physical space for research (lab space), possibly a joint appointment in a research department. etc.
if none of these can be part of the offer, this would mean your research activity is not supported.