Removed the manual DNS on the router, disabled PiHole on my old desktop, installed PiHole on my current desktop and added a manual DNS on the router on point to my current desktop. Everything seems to work, I just need to update the static DNS on the SmartTV and I will see how stable PiHole is supposed to be.
After installing PiHole, but before updating the router it forced my computer to reboot when it was not able to connect to the router. I suspect that could be the culprit, so I will have to see how often my computer reboots. I may want to install RPi Monitor on my current desktop as well.