Your username would fall under GDPR as personally identifiable information - also if your instance asks for an email address, that is also personally identifiable information under GDPR.
I think any posts that users can contribute to a social network, also fall under GDPR.
This is a potential issue that many instance owners may not have realised.
Since they are ZigBee, replace the Hue Hub with an agnostic ZigBee one.
Since you already use home assistant I would recommend this one - https://www.home-assistant.io/skyconnect/
https://zigbee.blakadder.com/zha.html - this is lis of supported devices, if you go for the default ZHA setup.
There are so many good ones out there there’s no reason not to use one.