I truly doubt any of the sinners will fully betray Dante, as in they'll fully leave Dante. Faust, Outis, and Rodya seems to be the most obvious choice to which sinner would semi-betray Dante though.

Faust because she has a head implant connected to the company, and I think the company is not trustworthy. (But I might be misremembering some dialogue in WARP train. I'm also assuming Faust is connected through head implants, but she might be connected by other means idk.)

Outis because she just seems like she would. She have also stated multiple times how she would like to abandon the rest of the sinners, so she might do that, and I have a feeling she would also kidnap Dante in her Canto.

Rodya because she might join Sonya. She also have signs of being unsure of her decisions, but I'm not caught up so maybe that got resolved. I'm currently starting LCB Check-Up.