Yes, telegraf should be run as a non-privileged user these days.
I just checked my installation on EL8, systemd runs as the telegraf user, file owner is root:root on all relevant files/dirs, with the following permissions:
drwxr-xr-x. on /etc/telegraf/ and /etc/telegraf.d/
-rw-r--r--. on /etc/telegraf/telegraf.conf and /etc/telegraf/telegraf.d/*.conf
