The original post can't help but remind me of a bunch of people I talked to a while back who just, absolutely insisted it was impossible for a well written character to care about one person and be ruthless to another. I have no idea why, it was absolutely infuriating trying to get through to them that empathy isnt 100% absolute and equally applicable to every single person in existance.
At any rate, I tend to like one a few things. One is paladin-esque characters with boatloads of self-righteousness, conviction, and the actual moral fiber to back it up. Those aren't too common since people tend to prefer their protagonists being 'flawed' and 'relatable' and stuff, and if they do want a character to be morally flawless they generally don't like making them self-confident and a bit conceited to go along with it.
Another would be characters whose only interest is protecting their kin, with absolutely no care for anything beyond that.
And lastly I honestly have a soft spot for just bloodthirsty blood knight types.
Theres a few more I like in theory but, in practice the execution to make me like them is so specific that I dont really trust any writer to do so and as a result just end up preferring that it's not done. But at least in theory I like characters who are entirely hopeless, accursed from the day they're born, etc. and compensate through sheer spite. To be clear thats not just like a character down on their luck who becomes hard and ruthless I mean more like, a character who has consistently only known misery their entire existance but will never cave or budge even an inch. Stubborn to the point of idiocy, uncompromising to a fault.