I’ve ran into the same problem install a system and couldn’t get online, it’s frustrating as you know what I’ve learned over the years to keep a folder on one of my drives with all kinds of drivers and files just in case.
One I ran into was the Nvidia driver for the video card no one offered it because it was a paid only driver that was a really head banging frustrating process but working my way through it I learned a lot about Linux. I don’t know if you know of this site distrowatch.com you can read and learn a lot there.
Best of luck I’m sure you will get it worked out just hang in there....