CAX80 vs Cell Phone

Just recently moved into new home with newly wired network cabling with 2 WAPs and chose a CAX80 to be my main router. Other than 3 cameras and 2 Smart TVs no other big wifi draws. Since move in, wifi has always been spotty, slow and drooped often. Learned to live with it but now my two Samsung TVs no longer have the internet channels (Samsung Plus), it is constantly trying to download and then blames the connection. Strange thing is all apps work fine on the 2 TVs. Even had Astound by to check internet service and it's 100%. Both TVs are connected to the router via ethernet but get same problems with wifi connection. Strange thing is, problem was solved when I connected the TVs to my cell Hotspot. That means something is wrong with the router, what could it be?