Go into the WiFi router settings and try manually setting the 5 GHz network to a channel between 36-48 or 149-165. The in-between channels (50-144) are DFS - dynamic frequency select. Not all devices support them.
https://en.wikipedia.org/wiki/List_of_WLAN_channels#5_GHz_(802.11a/h/j/n/ac/ax)
What happened is after the 5 GHz band was made open, researchers discovered that some of the frequencies right in the middle of it were very useful for a new form of doppler weather radar, which is now used at many airports. So the FCC went back and revised the standard. The 5 GHz frequencies are still open, but the channels which can interfere with weather radar are classified as DFS. WiFi equipment can use those channels, but if they detect weather radar being used, the equipment has to automatically switch to a different channel.
Some WiFi equipment does this. The vast majority simply block the DFS channels from being used at all (that way they don't have to waste time trying to detect weather radar). If you've got a router which supports DFS set to auto, it can end up on one of the DFS channels. But if your PC's WiFi adapter simply blocks DFS channels, you won't be able to see the router when it's on a DFS channel. The fix is to manually assign your router's 5 GHz WiFi to a non-DFS channel. (Take care to select a channel with 40 or 80 MHz bandwidth on the linked chart if you want to maximize bandwidth.)