Hi, author of the RuuviTag HA integration here 
MQTT with HA doesnāt (canāt) work out of the box because HA doesnāt understand the ruuvi/... topics and canāt translate them into sensor update payloads.
Iām working on a Ruuvi Gateway integration for HA that basically acts like the Shelly/ESPhome bluetooth relay that already exist. Since thereās no streaming āpullā endpoint on the Gateway (yet? 
) itāll necessarily have to poll the /history endpoint at a given interval, but I think itāll be fine.