How I restored my system when docker volumes wrote disk full

Boot from external usb stick and open terminal
Find main disk and /root partition – lsblk, or lsblk -f
Create mount point – mkdir /mydisk
Mount /root partition like that – sudo mount /dev/nvme0np3 /mydisk
Check what takes room – sudo du -h –max-depth=1 /mydisk
Docker volumes are in lib/docker/volumes directory (or similar)
Delete them – sudo rm -rf lib/docker/volumes/*