I have some spare change from the North American holiday season, here are my $0.02.
Currently I'm working at the company as a QA Engineer and it seem like the role is not dominant if compared to QC Engineer role. Is there any improvement that we can do to improve Quality Assurance rather than conducting audit.
If the company
really has a different set of functional responsibilities for Quality
Assurance and Quality
Engineering, my suspicion is that those strictly in the
Assurance group are primarily going to be limited to "getting good/efficient at their duties". Working with the Engineering group on Quality
Engineering is encouraged of course. If nothing else, the QA group could feed suggestions for process improvements to the QE team.... you may be assigned action items for Preventive Action efforts.
A narrative caveat about what I wrote above. The lines between Assurance and Engineering can be blurry, for many reasons. Some quality groups are very small. Some organizations simply can't imagine that members of a quality group (no matter their title) could "know better" than whoever the recognized (or simply 'titled') subject matter expert. This is why it is important to not simply 'nit-pick'... each squeeze should produce juice. Some companies have "quality engineers" but the companies don't support (or understand) quality engineering.
My personal experiences have been that organizations typically stay in the immature states (levels 1 or 2 on the CMMI hierarchy) and if they never reach a true "Quantitatively Managed" state they will
eventually backslide into one of the less mature states. My own view is that Quality Assurance is necessary to stay in a Managed or Defined state, but Quality Engineering is needed to get Quantitatively Managed or Optimizing state (levels 4, 5). I find it more rewarding to work towards the higher level of organizational maturity; if an organization offers such a path I would encourage anyone frustrated with a role designed to steady-state at a lower level to advance upwards in their career.