Follow instructions for installing Zabbix server 5.0 for Rocky Linux 8

Then follow zabbix instructions for installing timescaledb
and go to timescale docs

after executing "yum update"
there is no timescale package available for PostgreSQL 10:

psql --version
psql (PostgreSQL) 10.23
yum search timescale | grep 10

oldest supported PostgreSQL that timescale supports is 12.