One shouldn't base the idea of popularity on these kissing statistics because Minthara could not even be kissed for the first 5 months of the game's release - during which time every other companion (
while the player-base was at its highest for months) kept racking up kisses from the very first day, whereas Minthara did not even
have a working romance due to critical bugs nor even
had kissing implemented for months. Kissing came 5 months later for her as a
completely undocumented fix in a random Hotfix #16, by which point the player base naturally diminished and those that remained avoided Minthara like the plague due to her infamous reputation of being unfinished and broken (which 100% stands for her even today).
So
do not believe the lies the Larianites tell. These statistics are a big fat lie and if they had any sense they would've excluded Minthara from the anniversary statistics... instead of highlighting their colossal blunder with the character by mispresenting her as "the least kissed companion" due to their own failures.
Same goes for any other kind of popularity comparisons too because Shadowheart or Lae'zel or Astarion or Karlach all launched with fully developed base content that got perfected over time since release. They became popular precisely because the players had a proper chance from the start to fully immerse themselves into these characters.
Minthara on the other hand apart from being exclusively locked to a completely underdeveloped path of the story; launched in an abysmally unfinished and broken state too with the majority of her content not implemented at all, while her content that was in-game remained completely inaccessible due to numerous character-breaking bugs, trying to cover it up as "just a bug blocking 1400 voice lines of hers".
So this has nothing to do with popularity. The fact that Minthara as a non-companion character during Early Access was extremely popular in comparison to actual Origin companions at the time, says all there is to say about her true popularity.
