If you’re faking the location anyway, why not just insert it later in the process?
In terms of getting the stats messages that are sent, keep in mind that there two TWO distinct uses of an MQTT broker in a LoRaServer/Chirpstack setup, which could be the same broker, but often would be different.
The first broker carries the
gateway/ topics and sits between the gateway bridge and the LoRaServer/Chirpstack. If you are running the server on the gateway, then you certainly want to keep this broker internal to the gateway to avoid unecessary Internet round trips.
The second broker carries the
application/ topics with decrypted output of the server (and downlink requests backt through it). These you might set to a cloud type broken to make the data available - but the stats messages are not included here, as those are gateway topics rather than application ones.
If you want the “stats” messages on a cloud MQTT, probably you should switch from running the server in the box to running Chirpstack in the cloud, that way you can also use a newer version of it, you gain the ability to combine the feed from multiple gateways in the future, and you won’t have to re-register your nodes if the gateway box gets damaged or stolen in the field.