Hi @SamPo1 ,
Random profile selection also happens based on some criteria like "updated after ...", "created after... ", "has certain attribute" etc etc.
I would suggest to create audience using some time based attribute.
To limit the number of audiences in a segment, you can use - toggle to limit the number of profiles to rank-
https://experienceleague.adobe.com/en/docs/experience-platform/segmentation/ui/audience-composition
I hope it helps, Thanks!