Just got one of these on Friday. Setup was easy and speeds are great. Primary network is wpa3 for newer more secure devices. Guest network is wpa2 for an old tablet and a 2018 Samsung series 8 TV(firmware is current). For some reason the TV does not receive a DHCP address from the 5g gateway. Sometimes if I power cycle the router I can get it to connect to the TV but then most of the apps on my TV will not authenticate(Netflix,Hulu, Disney +). TV has no problem connecting to the hotspot on my phone or my Verizon jetpack. It only has a problem with the 5g router. Makes no difference if the firewall settings are on medium or high and none of the other 5 devices are having this issue.
Try switching the Gateway's Wireless security to WPA2 temporarily, as a test. Some devices do not handle WPA3 Mixed Mode / WPA3 PMF requirements correctly. Alternatively, connect your Samsung TV to Ethernet if you have Ethernet connectivity available on it.