And for best areas to do it, I'd focus on areas that are most desirable for tourists and/or locals - these will likely be most lucrative for you.  

Lange - For Act 74 (touristic projects) I believe there have to be multiple units, but I don't know the minimum.   

Austin has charm and it's a great tourist city.

We actually saw a surge in bookings after the shut downs were lifted because both markets are places where the majority of tourists, even in the best of times, drive to visit.

While I have zero experience in STR "innerhalb von Deustschland" I am curious as to why these specific areas- and while I don't know SFR legislation per region, with STR in mind I might only suggest to look into Berlin as a more lucrative area- thinking along the lines of tourists specifically.   

After all when I built the place, I was there to do tourist things.

@Tim WinterI read/heard somewhere recently that 80% of tourists that come to Prescott are from the Phoenix area.....

Sheboygan would have the added benefit of being a good short-term rental place as it is located near popular tourist destinations of Kohler and Elkhart Lake.

I’m expecting a drop in tourists who drive in to my Central Florida location.  

Ellijay is a great tourist spot and the property will appreciate in the next 5-10 years.