Change "Preferred Kernel" (to Conda Virtualenv) in Jupyterlab kernel selection dialogue

Good day, how can I change which kernel is shown as “Preferred” when starting a notebook in Jupyterlab?

I am managing a Jupyterhub server (TLJH), with Jupyterlab Version 4.1.5.
I would like the users to find one of the Conda virtual environemnts as a “preferred kernel”, is this possible?
I already tried changing the settings

c.MultiKernelManager.default_kernel_name = [...]
c.MappingKernelManager.default_kernel_name= [...]

in the files ~/.jupyter/ and ~/.jupyter/, but it has no effect on the Preferred Kernel.

this topic seems to be related, but there is no solution