iMac19,1 isn't supported in Tahoe.
If you want to use an iMac SMBIOS you need to use iMac20,1 or iMac20,2. As they are the only 2 x iMac SMBIOS that work in Tahoe. Apple have dropped all the others.
You have to plug in a USB2 and a USB3 pen drive/device to discover all 18 x ports. Each...