Also a premium user, I'd really like to see this! ICON CH is remarkably good in the Swiss Alps , and potentially as far as the northern Mediterranean Sea; although in the MeteoSwiss app one cannot pinpoint locations outside Switzerland, which makes it quite limiting... Having it in Windy would be great!
It could probably work similarly as ICON-D2 which falls back onto ICON-EU? https://www.meteoswiss.admin.ch/services-and-publications/service/weather-and-climate-products/weather-forecasts.html