An idle Wi-Fi client with no traffic should have a very minimal effect on your network's quality. The TV is only going to be slowing things down if it's actually using the network and downloading/uploading. Which regrettably, is a problem with smart TVs. But there's no reason to limit the number of idle clients on a Wi-Fi network assuming your gateway can handle it. The challenge is though in the real world many devices that should be idle aren't.
For my IoT network I just block most every device's access to the internet. That cuts down on a lot of their background chatter and gives me some minor protection.
Also honestly, I feel the majority of wifi problems could be fixed by having proper coverage (more access points), using hardwired access points (no meshing), and getting better equipment. I like Ubiquiti/Unifi stuff but other good options out there. Avoid TP-Link and anything provided by an ISP. If you do go meshing, insist on a 6ghz backhaul, though that hurts the range.
For my IoT network I just block most every device's access to the internet. That cuts down on a lot of their background chatter and gives me some minor protection.
Also honestly, I feel the majority of wifi problems could be fixed by having proper coverage (more access points), using hardwired access points (no meshing), and getting better equipment. I like Ubiquiti/Unifi stuff but other good options out there. Avoid TP-Link and anything provided by an ISP. If you do go meshing, insist on a 6ghz backhaul, though that hurts the range.