HA running on PI - how do I clean-up storage?

HA is running on PI 4 with 2GB RAM and 128GB SD card.
Currently, it is showing that 21GB storage is used:

I installed Terminal and after running du -sh -d1 it shows that used space is 9GB and from that 9GB 8.3GB is taken by HA db:

My question - how do I clean up the rest of 11GB without removing sd card from PI and putting it on SD card reader to read on some linux host?

Just 8 add-ons are installed, I have 21 devices in mosquitto broker, and from that 15 are Zigbee devices.