Multi-location Home Assistant - MQTT over intermittent VPN?

Installation
1

Does anyone run HA OS in a setup where some of the sub-parts are in a different location?

I have a situation where there are two sites, far away from each other (thousands of miles/kms). The remote site has non-existent internet connection, spotty at best when someone is present through cellular.

I am thinking of putting Z-Wave, Zigbee, WiFi devices at the remote location, a local MQTT broker, and bridge it to the primary site.

The idea is to fire up a VPN when internet becomes available on the remote site, and publish all the data.

With clever naming and grouping, I can identify and manage both primary and remote sites without an issue.

My only concern is that the local MQTT broker will just drop the data as it times out, instead of queueing it for the extended period, potentially months. There is power at the remote site, so things can run, just no comms.

Is there a way to do some technomagic where the locally queued up data does not expire/drop?

Is there an alternate approach?

2

I would either run two separate HAs or look into getting a cellular modem / router at the remote location. What is your aim here, to keep historic data?

3

Yes, keeping historical data to be able to look back.

No cellular service. Only Sat phone works. We are trying to see if we can get Starlink mobile in intermittently. Cannot afford to have one permanently on site.

Is there no way to queue the data?