Thank you to you and everyone here for your input! I thought I would post this information here, as many have asked about my permanent residency (Daueraufenthalt) in Austria. I hope this can also be of help to someone else in the future–
There is no automatic exchange of residency permit details or residency registration documents within the EU, the EEA or with Switzerland, so the Austrian authorities do not know where in Europe I still hold other permits or registrations, unless they specifically search for this actively in the European EKIS-database, but this is normally only done if I am suspicious of a severe criminal offence.
The permanent residency permit “Daueraufenthalt EU” does allows pretty long absences from Austria where I can really cancel ALL ties to Austria if I wanted to – I don ́t even have to have a Nebenwohnsitz then in Vienna anymore during these times. But these times strongly distinguish between leaving Austria but staying in the EEA or leaving the EEA totally, and in this case Switzerland is NOT automatically included in the EEA or EU-definition unfortunately. In Switzerland I could stay for a maximum of 12 months continuously, then I would need to return to Austria (within the EEA it would be up to 6 years).
However, I do NOT have to return to Austria permanently again after those 12 months, there has been a decision of the European High Court in 2020 (actually against the MA35 of Austria) which says that any provable presence of the 3rd-country national anywhere on the territory of the European Union, even if its just for a few days, is enough to “renew” these 12 months. Here you can read more about this case in English: https://curia.europa.eu/juris/docume…st&cid=9330035
The important part is at the very bottom:
“On those grounds, the Court (Third Chamber) hereby rules: Article 9(1)(c) of Council Directive 2003/109/EC of 25 November 2003 concerning the status of third-country nationals who are long-term residents must be interpreted as meaning that any physical presence of a long-term resident in the territory of the European Union during a period of 12 consecutive months, even if such a presence does not exceed, during that period, a total duration of only a few days, is sufficient to prevent the loss, by that resident, of his or her right to long-term resident status under that provision.”
So basically because I have an Austrian “Daueraufenthalt EU," I can live in Switzerland as much as you want to without losing my right to residency in Austria, as long as I make sure you stay somewhere in the EU for a few days at least once a year and can prove this with travel-documents, hotel-reservations, etc. For me, this is not a problem at all, as I work regularly in Austria, Switzerland, and Liechtenstein with various orchestras-- immer unterwegs!
Hope this clarifies matters for those curious or anyone else who needs to know for themselves!