@Harvy66:
PFSense is optimized to be a firewall and router, not an app server. In my experience, doing a speedtest to PFSense uses about 2x the CPU and I get a 5% reduction in speed than testing through PFSense. Testing through PFSense means that that bandwidth is actually doubled since all incoming packets must also go out. This means doing a speedtest to/from PFSense is about 4x more expensive per packet.
I don't see there being an issue having an app to do speed tests from pfsense. I know that my unifi USG Pro has an app built in to do speed tests and there are a few other firewall/routers that do the same.