C7000v2 wireless Internet cannot reach ends of apartment

In our condo apartment, a new Nighthawk cable modem/router cannot produce a wireless Internet 5G signal strong enough to reach the other end.  This is a COMCAST cable environment.  The distance fro one end to the other slightly exceeds 100 feet.  The router does throw an effective signal approximately half that distance.  I disconnected the router, moved it to a coax wall jack at the other end, and essentially the problem was reversed, meaning that it worked perfectly for a similar distance (halfway), but the wireless signal isn't sufficiently strong to be detected by smart TV or cellphones.

There aren't any coax jacks installed in between those points, and I am not permitted to install new wiring of any kind without obtaining an engineering permit from the condo management.

Here's my question:  can I install a second Nighthawk cable modem/router, giving me one at each end, and effectively providing wireless connectivity throughout?  If so, it would seem to provide a solution at considerably less cost than discarding the Nighthawk in favor of a mesh system.

Thanks for any advice you may be able to provide.