Honestly if Soi has increased her Durability but by the end she wins. Like between that it's kinda hard to say Starrk isn't a slouch in speed either and Cero Spam is a lot stronger than people realize but seeing that Starrk also has a motivation problem and she will be motivated to kill... I will say it's a High Def or a Draw if she is TYBW arc. 10 Year Time skip Soi wins mid-def but honestly that seems kinda unfair because you could probably grab anyone high captain level and if they trained up the whole time they could defeat Starrk and probably all the Espada depending on your opinion on Yammy and Ulquiorra. I think a More interesting match up for Starrk would probably be against BG9 and for Soi Fong probably Bambietta but I think both of them are kinda hard to tell who would win.