Hello Mimboiloo59
Saver Day Passes are valid on international trains as far as to the border station in Switzerland. From there, you need an international ticket. Thus, you have to split the train bookings into two separate bookings.
You can find the validity map of the Saver Day Pass here:
https://www.sbb.ch/en/help-and-contact/customer-service/praise-comments/claims-complaints.html
You are not allowed to declare Saver Day Passes in bookings of international through trains to benefit from discounts or seat reservations valid for the whole trip.
For Berin to Geneve, you must purchase an international ticket from Berlin to Basel Bad Bf. From there, the Saver Day Pass is valid to Geneva.
Kind regards,
Roland