Silootha92
Note that there are no regular “roundtrip” (aka return) tickets which are valid longer than one day. The only available single day based special fare would be the Saver Day Pass, which will be offered as alternative or as replacement to a regular point-to-point ticket directly in the SBB webshop.
Regarding multiple days / your entire stay, check whether some Swiss Travel Pass could make sense or not by comparing with the “regular” ticket prices according to the SBB website based on your detailed plans. I don’t think so, from what you revealed above.