mac mini m4 slow internet speed test

Upgrading from iMac 5K to Mac-mini M4. I have ATT fiber. The iMac consistently runs around 500mb in both directions and has for the last 5 years. The mini is sitting next to the iMac but never exceeds 100mb in both directions. Even with a hardwire connection to the ATT router the mini returns the same speed results. The network configurations are identical. ATT upgraded all of my hardware yesterday but the results stayed the same of both devices.