There’s now a fork of ESPresense (bluetooth based presense detection via ESP32s) that supports active polling of Mifloras and sending their data via MQTT in configurable intervals via the espresense ESP32, so one can use the same ESP32s for multiroom presense detection and connecting to the Mifloras across the house, circumventing range issues without additional hardware. You can configure which Mifloras to poll in the ESPresence UI so if a Miflora is in range of multiple ESP32s, it does not get polled from multiple sources.
For basic OpenHab/ESPresense integration, see, e.g. here Step-by-step presence detection with bluetooth tag (e.g., GTags) and ESPresense on ESP32 - #9 by simon20
ESPresense official: GitHub - ESPresense/ESPresense: An ESP32 based presence detection node for use with the Home Assistant mqtt_room component for localized device presence detection.
ESPresense fork with Miflora support: GitHub - 0Flush0/ESPresenseFlora: An Espresense fork that supports the MiFlora plant sensor
Not sure to what extent the fork will be maintained; and auto-updates will remove it, I guess. So, if you’d like to see this integrated in the ESPresense official releases, maybe add a comment to the relevant issue here: Feature implementation: Xiaomi Mi Flora plant sensor · Issue #720 · ESPresense/ESPresense · GitHub