Exactly the same issue here. Ordered a few minis to get better reception than when using a single hub but everything for me is connected to Home Assistant. I should have, but hadn't noticed that the hub mini doesn't have the SDK.
This repo is GPL licensed, but it should be an easy template to implement Home Assistant support via MQTT, but not being able to use the SDK on the mini makes it useless:
https://github.com/id628/flic2hass
If the hub would be able to connect to MQTT and publish events it wouldn't even need to add the HA Discovery stuff, we would be able to do that ourself.
Smart home devices like these should have first class MQTT support nowadays.