ElectricEel-24.10.2.2 running increasingly slow

I’ve been running my media server on TrueNAS scale for a few years now. I haven’t added new apps recently, but in the last six months, the server seems to be running increasingly slow. The CPU and memory monitor on the dashboard makes it seem that the server is doing nothing. My app data volume is 70% full (mirrored 1TB SSDs) so I wonder if that may be the issue. I am running a few apps in the TrueNAS Applications and a bunch in dockage. Where can I start troubleshooting this issue?

Server: ElectricEel-24.10.2.2, 2x Intel(R) Xeon(R) CPU E5620 @ 2.40GHz, 128GB RAM

At least I figured out the App data storage issue. Had too many old images. Cleaned that up and got back down to 52%. Still running poorly though.