Mentoring roles
Academic supervisors are usually extremely busy.
Supervisors are sometimes min-maxed to producing articles at the cost of other skills.
This leads to a situation where the supervisor can’t provide all of the needed mentoring. Maybe they can give a great idea and write a good people, but not tell someone which tools to use to do it well.
What is a research engineer?
Someone that works on making research work well, not simply focused on making the next academic level or getting more first author papers.
So they have time and freedom to do useful mentoring.
Thus, they are designed to help grow your research and can mentor in research processes.
Common names: Staff Scientist, Laboratory manager, Research Software Engineer.
Have time to co-work rather than just tell people what to do and wish good luck at it.
Research engineers to support your group
But you can also hire people with the explicit purpose of supporting your other researchers, instead of someone with the goal of advancing their own career.
HR may not allow this since they don’t fit in the hierarchy.
You probably can’t do what is suggested here, but it’s something to think about.