Okay, let's try the Following. Open in the Folder with the .deb File a Terminal. You can do that by right-clicking on an empty Space in the Folder and choose in the Right-Click Menu the Open ''Open in Terminal''. In Terminal type
david@david-iMac:/media/david/AEE8-DEAD$ sudo dpkg -i dkms_3.0.11-1ubuntu13_all.deb [sudo] password for david:
Selecting previously unselected package dkms. (Reading database ... 251351 files and directories currently installed.) Preparing to unpack dkms_3.0.11-1ubuntu13_all.deb ... Unpacking dkms (3.0.11-1ubuntu13) ... dpkg: dependency problems prevent configuration of dkms: dkms depends on gcc; however: Package gcc is not installed. dkms depends on gcc-13; however: Package gcc-13 is not installed. dkms depends on dpkg-dev; however: Package dpkg-dev is not installed. dkms depends on make | build-essential; however: Package make is not installed. Package build-essential is not installed.
dpkg: error processing package dkms (--install): dependency problems - leaving unconfigured Processing triggers for man-db (2.12.0-4build2) ... Errors were encountered while processing: dkms david@david-iMac:/media/david/AEE8-DEAD$
That wouldn't be enough. From Your Output, You see that You need more Packages.
Does Your iMac only have Wifi or can You connect a Cable to it? If yes, plug in an Ethrnet Cable and then You should be able to install the actual needed Driver.
Alternatively, You could plug in Your Smartphone and use that as Connection.