You can use the TV to pull media from the MC Server by finding and starting the appropriate App on the TV. I don't have a Samsung anymore to look at, but on my Sony the Apps are "Music" for audio and "Video" for video media. Once the App is running, look for a way to search for a select "Devices" or "Computers" or "Servers". You should find your MC Server listed in there. Select it and it should load information from the MC Library.
Actually, come to think of it, the Samsung I used to have may have let me select a DLNA Server such as MC in the Source listing on the TV, and then I could select contents and play them. Maybe a Google of how to do it would answer that question.
But that isn't a great experience, to put it mildly. Most TV Apps just let you scroll through long lists of media files, with little search capability. They are frustrating to use. Also, for example, the Sony Video App will happily show the Audio, Image, Podcast, and Video "directories" in MC, but will only let me play video. There is no one App that plays all media types on the Sony TV.
To the firewall. First, I use a Norton firewall, so can't advise exactly. But I know it is almost impossible to completely turn off Windows Defender. Even on my PC that uses Norton, Windows Defender will block some traffic during bootup at least. So I think the best idea is to turn Windows Defender back on, and make sure it has the correct rules.
First, check if MC can see the HTTP Messages/Calls being sent by the TV, if it is sending any. My TV is visible now as a renderer, and I can play Audio, Video, and Images to it, when connected from my Workstation installation of MC. When I run MC with the TV turned on I can go to;
Left Navigation Bar > Services & Plug-ins > Media Network > Select the MC DLNA Server associated with my TV "DLNA Media Server: Amintha (Sony TV)" and I will see HTTP GET and POST messages being from the TV to my Workstation. The TV is IP Address 192.168.0.12 and my Workstation is IP Address 192.168.0.10. See that attached image.
So, if I am interpreting that information correctly, my Workstation is allowing Inbound HTTP Messages/Calls from the TV. If I am wrong Andrew or anyone, please correct me!
Selecting the "DLNA Subscription Server" on that Media Network page also shows DLNA Event Notifications. See the second image.
You may want to check if you are seeing the same sort of Messages/Calls for your TV.
Interestingly, if I select the "Device discovery server (SSDP)" on the Media Network page mentioned above, I don't see any SSDP broadcast messages from the TV, which I would expect to see. I think that means that the TV isn't advertising itself. Yet DLNA Servers and Controllers see it. That is a mystery.
Anyway, back to the firewall issue. Given that my Workstation can see Inbound HTTP Messages, I went looking for a firewall rule that was allowing it.
I thought this one might be the rule, since it is called "Default Allow Media Player Sharing - HTTP (Private Network)". But it restricted Communications to port 10243, so no go.
Action: Allow connections that match this rule
Connections: Connections from other computers
Computers: Any computer in the local subnet
Communications: The rules will apply only if it matches all of ports the listed below: TCP, local port 10243
Advanced: not relevant
Description: Default Allow Media Player Sharing - HTTP (Private Network)
That rule sounds almost correct, but the actual communications are happening on ports 52101 an 52104, in the examples I posted above. While I have mostly seen ports in the range of 52100 to 52200 in the past, consistent with what I know of MC use of ports, I have seen port 52323 used at one time.
One of the two rules below, or both if these Messages are TCP rather than UDP, are probably what is allowing MC to see the Calls. I haven't tried to work out if these Messages/Calls are using TCP or UDP packets.
Action: Allow connections that match this rule
Connections: Connections from other computers
Computers: Any computer in the local subnet
Communications: The rules will apply only if it matches all of the ports listed below: TCP, All types of communication (all ports, local and remote)
Advanced: not relevant
Description: Default All Windows Media Player Sharing (Private Network)
Action: Allow connections that match this rule
Connections: Connections from other computers
Computers: Any computer in the local subnet
Communications: The rules will apply only if it matches all of the ports listed below: TCP and UDP, All types of communication (all ports, local and remote)
Advanced: not relevant
Description: Default All Windows Media Player Network Sharing (Private Network)
So look for the rules above, or similar, in your Firewall. If you don't have either, you may need to create them. Unless someone else speaks up with better information.