Had a question on just the general approach to automate tasks that need to run on specific machines in the environment? Like I would like to get my database backups scheduled through Prefect, so should I have a Prefect agent installed on my backup server so I am able to kick off that task with shell? This is in addition to my other jobs which are more client-specific ETL tasks able to run from just about anywhere behind my firewall without issue

If the backup task has to run on a specific machine, then running an agent on that machine would be one way to do it. You might also write your backup task to operate remotely (say ssh into the backup machine and execute), up to you.