ah ok you are still on debian stretch. Looks like uninstall - reinstall caused some inconsistency on your system. pls can you do the following
sed -i '/netdata/d' /var/lib/dpkg/statoverride
dietpi-software reinstall 65
once done pls create the following 2 files and copy the content from attached zip file
nano /etc/netdata/netdata.conf
nano /etc/netdata/edit-config
netdata.zip (1.45 KB)
once done restart netdata and check status
systemctl restart netdata.service
systemctl status netdata.service