Yeah Jeffery is the best <3
I still hope he'll be the ML. I mean as far as I know, this isn't based on a novel and raws aren't far ahead so nothing is confirmed yet. If you think about it, she has those hottie disciples but they're like her kids. She basically raised them so I don't think she'll be with any of them. I don't think she'll be with any new character either. That doesn't make sense. Also, the demon king seems to be possessing her disciple or something so I doubt it'll be him either.
I say Jeffry has the highest chances unless the author/artist is going to go for a tragic ending where she dies before getting together with anyone which I also doubt. Even if she dies young (relatively young seeing as she is hella old), I think the author isn't going to deny her the very reason she came back to life.
So if she is definitely going to have a romantic partner before the ending, if it's not Jeffery, I don't know anyone else more fit for it

I feel kinda sad that this emperor desciple who looked like he had a very close reltionship to her does not recognize her. Yes, he has some doubts but he already judges her to not be his master and is merely looking to confirm that.
Now that I think about it, crazy mana desciple also didn't recognize her when they met twice and only knew who she was when she stopped his rampage upong their second meeting.
I don't want to sound too poetic but the way they had a connection to her in the past, I thought that even if she reincarnates as some guy with no memories of her previous life, they'd all recognize her right away but maybe it's too unrealistic.
Rogue desciple was right on the money from the start so that's nice...Although I think the reason is more like the thing that infected him and turned him dark probably recognizes her more than his normal side