Could my ISP be blocking Cloudflare traffic on my Samsung TV

Yes, it's possible. Some Internet Service Providers (ISPs) implement traffic shaping or filtering that might inadvertently block or degrade traffic to Cloudflare's servers. While uncommon, it can happen. You can try contacting your ISP to inquire if they have any policies affecting traffic to cloudflare.com. You can also temporarily bypass your ISP by using a VPN to see if that resolves the issue. If a VPN works, then the ISP is likely the problem.