How would I find the total amount of devices that are sending logs to RSA Security Analytics, SIEM?

[EugeneSteslicki]

SCCM is of no help because it's only logging windows devices

[EricPartington]

Try Admin > health and wellness > Event Source monitoring

you can set filters on when a device was last seen or sent logs and filter by decoder or vlc (forwarder).

[HemantKumar1]

Also, you can run a report where device IP exists