Searching for a "blacklist" of removable drives shown in the dock did not lead to anywhere.
The only thing that can be done is to disable the display of all or of none icons shown for removable/mounted devices.

Is there an option planned to be able to select e.g. only USB/DVD whatsoever volumes to be displayed in the dock instead of showing also mounted devices which I mount at startup (e.g. a bigger disk for data, which I do not need to be shown in the dock, as it works for me in the background and the icons just fill-up my dock)

Ubuntu Version is 19.10

br,
Kurt