Hi,
I am using a workaround since my request (Not possible to integrate multiple InfluxDB databases/buckets · Issue #106849 · home-assistant/core · GitHub) was marked as “not planned”.
I have disabled InfluxDB as target for HA and limited the regular (in my case SQLite) database to a few weeks and for several sensors.
My InfluxDB has several databases with differing retention policies etc.
I use good old Node-Red to send data to InfluxDB. Bit of a hassle to setup initially (pull each sensor in NR, do some transformation to build the right message etc.) but has been running for several months now without issues.