hmm, how about some bad end routes. like for example as the game starts it goes though the motion of just before he ends up in the new world. and has a few options to pick for albedo's flavor text settings. one of which leading to aldebo going above and beyond renner level yandere to ainz. maybe [crazy in love with ainz] being the flavor text change. with the cannon [is in love with ainz] and maybe some joke option of [is friends with benefits with ainz] which would still lead to cannon path with only minor text differences and more comedy due to slight differences in albedo vs shalchair spats.
but that setting only after being compounded with neglecting albedo leading a bad end where either ainz accepts a life of being chained up in albedo's room or whatever. with the alternative option of being forced to kill her and accepting the long term consequences of one of nazz's biggest assets being lost.
probably more easy bad end routes could be ainz (presumably having never lost shalchair to brainwashing) going into a real fight (not a test the waters psyop like the fall of the kingdom cannon PDL fight) against PDL or one of the other dragon lords and utterly underestimates them. where the player themself had to choose to grossly underestimate them. so another series of bad mistakes compounding into a bad end.
I never put bad end routes in my games, but I do put alternative routes that may be considered "bad" if you're looking for something specific.
For instance in Overlord H you had different choices with Clementine, if you killed her like canon, Shalltear would have the same fate. However, if you spared Clementine, Shalltear would never end up like that and you also got another heroine (Clementine).
There'll be many such choices, some different than Overlord H.
As for Albedo, she is already as Yandere as she can be, but she respects Momonga for staying behind. He's also very powerful, which also helps. She has/will assault him for sure, but it's due to Momonga allowing her to rather than being powerless.
Shalltear would be able to do it, but it would be pretty short lived since the rest of Nazarick would be loyal to Momonga.
Also she (or any other) would never willingly betray the only supreme being who stayed with them.
also on a side note, i'd like the name change issue after ainz changes his name to such being explored. if i remember right in canon albedo has at least a bit of an issue with it. and it was ignored in overlordH i think?
No it wasn't, there was even a whole mirror scene for it. She even continues to use his original name in private if I recall correctly, and only addresses him as Ainz Ooal Gown in the right settings. (That was a neat thing I had decided to add since the canon shows that NPCs are conscious now and can decide for themselves, like Aura did during Shalltear's fight, despite her orders being different).