Veecouhuer14
The GA Travelcard for Seniors for 275.- monthly payment is not applicable in your case, as the minimum contract duration for this Senior GA is six months, not two. (There is also a separate “1-month GA Travelcard” available for 440.- though, without senior discount)
With the Swiss Travel Pass flex you have to consider that many museum-type entrance fees are included, such as e.g. Chillon Castle, everything in and around Gruyeres, or Ballenberg.
Depending on the number and length (read: ticket costs) of your planned trips, especially since you’re looking at shorter ones, two of the following could also make sense: Swiss Half Fare Card , which is a 1-month “tourist” version for 120.-, available only for foreign residents.