Run dmesg and see if you find anything suspicious of the cause. If you find something like “blah blah… Ethernet… Blah blah… Key was rejected by service” or similar, it’s due to secureboot.
If this is actually related to secureboot your drivers are most likely not in tree and installed via dkms, so they need to be signed or secureboot won’t allow them. You can setup a machine-owner-key to sign them yourself, and you can setup dkms to automatically sign them using that key. The instructions are on dkms’ readme. After setting up you need to run dkms autoinstall or manually reinstall the drivers to trigger the automatic signing.
Edit: I just noticed you said you deactivated secure boot… I have no clue. But for future reference, you can sign your modules to work with secure boot, it’s not a bad idea.