My suggestion would be to configure your own router using a Linux distro. It's not as difficult as it sounds, the kernel already does most of the heavy lifting. All you need to really do is enable packet forwarding and configure the firewall using iptables rules (block all in, allow all out is a reasonable default). I use Unbound as my recursive DNS resolver, together with Hagezi's blacklists to provide DNS filtering. I filter ports 53 and 853, and filter by IP known public DNS servers (Hagezi maintains a list). DHCP is provided by the isc-dhcp-server package on Debian.

That's a more or less complete home router, with plenty on spare resources to run internal or external services like a Wireguard tunnel, file server, or the Docker/Podman runtime.

That being said, I still wouldn't connect a "smart" TV to the Internet. There are better options like a Linux HTPC.