First of all, elephant in the room and huge concern to me personally: Information about every single previous stay, for the past 1+ years, was left in the apartment. This means that whoever stayed in this apartment I saw the following information about you: Your full name, your full residence address, your contact details, who you were traveling with, your and theirs date of birth, your document ID, who issued your ID/when/and where, the date of your stay, and your signature. This is absolutely unacceptable and illegal (GDPR rules about safeguarding personally identifiable information). I will be reporting this to the Austrian data protection office, and airbnb.
Other than that here are my thoughts about the apartment itself:
Everything that's higher than what the maid(s) can reach is dirty, normally I'd let this slide, but during global pandemic a shelf that I can easily reach should be clean. With 2 fans in the apartment who knows what kind of germs, bacteria, and viruses accumulate at higher places. The host responded that they would need to get ladders for the cleaning personnel in order for them to be able to clean it. My suggestion: Then do it. Small 2-3 step ladders are small enough to fit in the apartment.
The apartment is very very hot during summer, and opening window at night was not really an option for me because it's right at the street so there's a lot of noise coming. I found it very hard to sleep and stay in due to the heat.
The place is close to the public transportation and as such everything is easily reachable.
Tha are the apartment is located in is, well, not really middle/upper class area - let's put it that way.
Overall the carlessnes about some of these issues is what makes me unable to recommend this apartment to others.