Multiple issues with build

Hardware: Gigabyte Z390 I AORUS PRO WiFi, Core i5 8500 CPU, 16GB RAM, using iGPU.

Have been (and still) using OpenCore 0.5.9. SMBIOS is set as iMac19,1.

I built this Hackintosh back in early July with Mojave. Everything was fine. There were no issues except the SSD died. I replaced the SSD and re-built it and it was working fine again until about a month ago, where all of a sudden, the Ethernet port floods the Ethernet switch as my Plex Server running on this Hackintosh records a show from my HDHomeRun (on the same switch) and then it kills two of the four Ethernet ports throughout the home. Not all ports are affected, only two ports in particular out of four. It also kills the connection to the NAS in the basement, but somehow, it can send an email telling me the NAS has gone offline. Strange, but weird.

Restoring the Carbon Copy Cloner image did not improve things. The system flooded the network and brought it down three days in a row last week. So, for no reason, I then tried to install Catalina instead. I started yesterday, and got it up and running with all updates installed. Everything ran fine, but App Store wouldn't accept my log in. Nothing worked. I was able to log in to iCloud with System Preferences and Calendar, iMessages, Notes, iCloud Drive, etc. were all working. I deliberately entered a wrong password for the App Store app and it knows the password is wrong right away. It just won't accept the correct one.

Overnight, I downloaded the latest Catalina using gibMacOS so I dodn't have to apply the combo and supplemental updates that were released last week. My original Catalina package was from July. I think it was still 10.15.4 at the time.

So, this morning, I started from scratch installing Catalina again. This time, it's the 10.15.7 version. It ran fine for about two hours, but it rebooted for no reason after everything was installed while it was recording a show with Plex Server. I didn't notice it until I looked at the show I was recording and it wasn't there. I connected with VNC and I was at the log in screen. After I logged back in and let it sit idle for a few hours, it then lost USB connectivity. I discovered this as I was trying to connect an external drive so I can do an image backup with Carbon Copy Cloner. I plugged in the external drive into various ports and the drive was not mounted. The wired mouse and wireless keyboard also were not working. Since I have done all the setup, it has rebooted itself three times now. All three times it rebooted, it was recording TV with Plex. However, in between, I did try to record some random shows and they were recorded properly without rebooting. Plex recordings go into a separate SATA hard drive, not the same SSD where is OS is installed. I have no idea what's happening. Well, at least this time, it wasn't killing connectivity with my other devices in the home... There is probably not enough information to diagnose the problem, but I hope someone would be able to tell me how to fix this or should I just give up and go back to Linux.

Mojave was running fine for four months. I just don't understand why all of a sudden there are all these problems. Sorry for the long, rambling question.