Why make life difficult for yourself.
If you want to complete your flight training in Portugal, study hard for the theoretical exam at home and take the exams while in Portugal and do the flight training there. Portugal will issue you an EASA licence which you can convert to a Swiss licence if you want to do that.
I personally don't see any reason to convert an EASA licence though. You can fly with it in Switzerland too.
I leave in Germany and have EASA licence issued by the UK CAA.
WP