But but, muh yaoi ship.Yup. Know that body type from a mile a way.
But yeah, giving the grandma the benefit of the doubt, I think she is just secretly over-protective of her granddaughter in a tsuntsun way.
We don't know yet what the matriarch is planning for Myaro initially. I think Myaro's mother is more like a broken figure (she technically became a school "slut" sleeping with many boys at school) probably because she gave in to the pressure of supposedly becoming the next head/matriarch of the Gudanviel clan (probably due to the grandma's push as well) - and I suppose the grandma already gave up on her as well. Now she probably wanted Myaro to grow up ruthless (not exactly spoiled and condescending towards others), so Myaro can keep her own in the dubious industries of the underworld (just like yakuza clans in Japan which operate on the legitimate businesses as well). She probably wanted to make Myaro the next matriarch so bad that she's becoming this ruthlessly desperate. Well of course, Myaro is very talented as a witch after all, so grandma really doesn't want her gone.The things is, how do you raise a successor to a criminal family? I feel like the grandma witch failed already. Myaro is a good person, after all. You need the successor to be a ruthless, heartless person. How else would they run a business of extortion, theft, and violence? Either the successor needs to be brought up as a spoiled douche looking down on everyone or as a person who lost pretty much all of their humanity (if it's correct to say that since they aren't humans in the story). The mother seemed to have become such, but the grandma's efforts, while hurting Myaro, didn't make her lose her kindness or honour. If the knight father had become a violent drunk who had beaten Myaro repeatedly, the grandma might have succeeded in creating a successor.