InfluxDB remote storage
You might have better luck on the InfluxDB forum. You are well outside the supported openHABian config at this point and there are few experts in InfluxDB on this forum. The problem and solution really doesn’t have anything to do with openHAB.
InfluxDB remote storage
/etc/default/openhab is only read and applied when OH starts up and even then it’s only applied to the OH process. It doesn’t add these environment variables to all processes running under user pi. Once you change this file you need to restart OH for the changes to apply. and they are only going to apply to the OH process and nothing else.
And answering anything to /etc/default/openhab is never going to be seen by InfluxDB which runs under it’s own process and usually under it’s own user.