Some hopefully good news for everyone. At the BAG (public health dept) press conference today, it was announced that the plan is to set up a national certificate issuing system for tourists which will hopefully make things more efficient for visitors and ease pressure on individual cantons. This is supposed to be operational by 11 October. In order to allow time for everyone to get certificates before travel, the "transition period" where foreign proof of vaccination is accepted will be extended until 24 October. Proposal will be in consultation until 28 September - don't see why it wouldn't be approved though.
Scroll down to the section titled National registration point for COVID certificates:
https://www.bag.admin.ch/bag/en/home/das-bag/aktuell/medienmitteilungen.msg-id-85254.html