You may be confident, but experience has shown that cables should never be trusted. I recommend adding your system’s details to the Linux Hardware (LH) database using hw-probe (installed with dnf). To rule in/out Fedora, I suggest running a live USB for another distro where your hardware is shown as working in the LH database.
Random “events” may be due to problems with power supply (maybe for your router). Is the router powered from a UPS?
Have you recently experienced a lightening storm or power surges? I once had a network card that starting glitching. The vendor’s diagnostics said it was fine, but physical inspection revealed fried components. Replacing the card stopped the glitching.
Can you borrow another router from friend/neighbour? I keep a couple old Apple Airport Extremes for troubleshooting – the build is very high quality and they can be found on ebay for under $20 or in the junkbox at local independent Apple dealers.
A bit more history and hardware details would help. Did both network interfaces work with some other OS (Windows, older Fedora, other linus distro)? There may be more detail from journalctl. Do you have other systems that work reliably with the same router?
Because this is random, it might be easier to also just run a terminal in the background and pop over to it when the issue occurs. You could weed it down some with: journalctl -fk
Following the output of kernel messages (like dmesg)
journalctl -f -u NetworkManager.service
To follow the output from NetworkManager