If instead parameters are defined externally in dblib, its visibility is controlled by ' Visible On Add' column. If some custom concatenation or truncation required, a text string object can be placed manually as a part of schematic symbol in a form of special string. Inclusive of other user-defined parameters on unmanaged components of schlib, visibility/color/font/location can be controlled in SCHLIB List panel, with panel display scope in blue text at the top set to ' Edit all objects from all components include only Parameters'. It is worth noting that for system-defined Comment and Designator parameters, 'Override Library Primitive' option in Preferences, Schematic » Defaults, under Primitive List section, can overule the corresponding setting you have in your library for each component.

The component designator and comment are now displayed and their location/font can be changed. Enable the Show Comment/Designator option. The Library Options are now displayed in the Properties panel. Open the Schematic Library document ( *.SchLib), and go to Tools ► Document Options. Configure location/font/size/color/visibility of comment, designator, as well as other parameters Starting in Version: 18.0

Altium schematic