One of the mantras of university is that research improves the quality of teaching. However, Loyalka and others (2022), suggest the opposite: "... research has a negative effect on student learning, suggesting direct trade-offs between the university’s dual mission of producing research and learning ...".
The researches looked at test results of about 5,000 third-year computer science and electrical engineering undergraduates is China, India, and Russia. They also surveyed instructors as to how many papers they published. A quasi-experimental research design was used to show a causal relationship, not just a correlation: more papers, poorer student results. However, I suggest there is a possible third factor: teacher training. It may be that productive researchers don't spend as much time learning to teach, & so are not as effective educators.
It may also be that good researchers have a different attitude to students to good educators. I recall a study at University of Canberra (which unfortunately I now can't find), which found that their PhD tutors who had not undertaken teacher training tended to help the better students, whereas those with training helped the struggling students.
I have met many researchers who are well respected in their discipline, who erroneously think they therefore know how to teach. Their false assumption is that teaching is about knowledge transfer, and easy to master for someone with considerable knowledge. As a result, these researcher make very basic mistakes in teaching, wasting a lot of their time and frustrating their students. This is unfortunate, and it is very difficult to convince them to undertake even basic teacher training. The solution, I suggest, is to train academics when they are starting out, when they can be compelled to undertake training.
There are, of course, other solutions, such as education only academic positions, and institutions. However, that would require a restructuring, and make marketing of courses and institutions difficult. Even if teaching only staff and institutions produce better graduates, this will be difficult for the students, government, and the public, to accept.
Loyalka, P., Shi, Z., Li, G., Kardanova, E., Chirikov, I., Yu, N., Hu, S., Wang, H., Ma, L., Guo, F., Liu, O. L., Bhuradia, A., Khanna, S., Li, Y., & Murray, A. (2022). The Effect of Faculty Research on Student Learning in College. Educational Researcher, 51(4), 265–273. https://doi.org/10.3102/0013189X221090229