Sorry to hear you are having so many problems with Airbnb/your guests that you have had to open multiple cases. @Si6
I've been hosting over 5 years as a SH and had an issue with a guest a couple of weeks back and they answered the phone after five minutes so I am not sure you being a long standing SH means worse service.
It sounds like in common with many other hosts who have reported problems here that you are caught up in a combination of Covid meaning they are inundated with calls at the same time as they have made cut backs in staffing.
What issues are you encountering - perhaps someone on this community can help?