On a WMS service there is an option to set configured projections.
These projections are advertised alphabatically on the WMS layers.
Suggestion is to use the order as configured in the configuration panel.
Common WMS clients do display a list of available projections when adding to a map, it makes sense to put more relevant projections for a use case on top, by configuring them in a specific order in GeoServer.
To be verified:
does the WMS spec require a specific order