Usually if your map is "not rankable" that either means it utilises an abuse of the editor in some way to achieve a goal - such as BPM changes solely intended to amplify the already existing SV usage - or it has patterning or structure which needs serious revision. Although technically the only factor a loved map requires is engagement, in practise a map at the very least needs to reach a level of quality we are satisfied with such that we believe there will be people who will be happy to play this map years down the line (especially since there's no PP reward in loved). We do relax this when a map is old enough (say, 5+ years) but still popular enough that it's regarded as a classic, but maps like this are quite rare.
For what it's worth, trying to force something into the loved category will never work without bribery. If you can advertise and improve your maps well enough to gather a solid concurrent audience, such as in mapping related Discord servers, through modding queues or through multiplayer lobbies that are happy to have a look, then that will be a big plus.
Also, this is from the point of view of mania - though I imagine the other gamemodes have similar stances.
Good luck!