Hi,
I can guarantee only what the help center says here :

There's no wording on that Help Center regarding where that cluster is deployed, and how, so, as long as it's that version, it will work.
The condition to "be in the same network" is not in the Help Center, but I stated it for your awareness, because you, as a customer, need to be sure that the connection between ThingWorx and Influx be of a good quality so that you don't have lost data, etc. That was the first thing that passed through my mind, but if you have a good connectivity between TW and Influx, that will absolutely work without needing to be in the same network. The reason I put the statement here is because I heard a couple of times of VPN tunnels that need to be established between local sited and cloud, and then those tunnels did not seem to be stable, they disconnected, etc....These types of conditions are usually well understood (and in their scope) by whoever is doing the deployment (like the condition to have good connectivity from ThingWorx instance to its internal database, PostgreSQL/AzureSQL/MSSql etc.)