How to get reliable WiFi?
For Spiel und Objekt, we use a Ubiquiti AP AC Pro WiFi Access Point. In order to get it to work, you also need one Ubiquiti ER-X Network-Router and one Ubiquiti Cloud Key.
This Setup has been reliably in use for the past 4 years.
We have decided to use, if possible 5GHz WiFi bands (usually, your at-home WiFi is on 2.4GHz). See also: WiFiBasics
There are two different things you should do: If you are lucky and you managed to get a contract before the beginning of the rehearsals try to get WiFi with connection to the internet into the contract. If you really want to be secure check down and upstream. Usually upstream is problematic in Germany. This will seem unusual for almost all theaters, but the contracts are just templates in which you can negotiate details beforehand. It just gives you a bit more leverage after you found out they promised you wifi but there isn't any. Also, make sure that not only the rehearsal space has wifi but your artist accommodation too. Many theaters are run by the city or county and they have strict laws about using their internet. Therefore the challenges that must be faced to use a hotspot are completely absurd. Alternatively, you can order a Gigacube from your budget or try to find out if the theatre even has one. The problem is that it will be limited to 50 GB a month. Make wifi a priority and explain that it is not just comfort. It will save your day if you have it up and running.