Unfortunately, we currently have no information on when the item will be available and when we will be able to deliver it. As soon as something changes in this regard, we will post it here. Sorry.
They cannot influence the performance of the SIM card subscription - at most they can increase it a little if they add 5G - but that depends on the location of the house and the mobile phone antenna. Also important: that all cameras can be supplied with sufficient WiFi signal.
I would just try it and clarify first: Do I have enough mobile signal for camera surveillance...?
You can find a comparison of the Arlo service plans here: https://www.arlo.com/de_ch/serviceplans
You don't need to buy anything else, the station is included. If you have a good Wi-Fi network you can also buy Arlo Pro 4, there is no need for a base station, the cameras can be connected directly to Wi-Fi.
Probably not, or only with a downgrade of the resolution, because Arlo Pro 3 forces you to subscribe if you want to use the cloud function. The only option is local storage. It works, but it is cumbersome.
The base station is connected to the Internet and the power supply by means of a cable. The camera itself has a battery and is connected wirelessly to the base station. The battery is supposed to last 6 months, but there is an extra-long charging cable in the accessories so that it could be constantly connected to power. https://www.arlo.com/ch/products/accessories.aspx
Yes, the cameras only communicate with the base station - the base station in turn has to be connected to an existing router.
And yes, if the cameras have no signal / no connection to the base station, the whole thing does not work.