Advice Request [HELP] IOT vs guest Wi-Fi vs Ethernet: security concerns

[Tiamati]

Hello! First of all, ty for your help. Let me explain my problem.

I'm currently using an old Philips smartTV, which the last update is from 2014. So I believe it probably has a lot of vulnerabilities issues.
According to some articles (here and here), all IOT should be connected to guest wifi, as they isolate those things from your home network. That's what I do. However, my old tv also can't connect to 5Ghz wi-fi what causes some performance problems. So, I considered changing it to an ethernet connection as I could easily connect the SmartTV to an ethernet cable.
However, IDK if I could isolate the TV from my network in the same way I do with the guest wifi. Do you have any idea?

Btw, my d-link router (EXO model) has a so-called Triple-Play option into VLAN section. Idk what exactly is that, but I wonder if it could help. (I'm posting a print of the function in case you wanna help me with that too)

Spoiler: Triple-Play print

 

[HarborFront]

You can read up something on VLAN here

Using VLANs for Network Segmentation and Isolation

Using VLANs for Network Segmentation and Isolation - RouterSecurity.org

routersecurity.org

 

[Tiamati]

You can read up something on VLAN here

Using VLANs for Network Segmentation and Isolation

Using VLANs for Network Segmentation and Isolation - RouterSecurity.org

routersecurity.org

I'll take a look. Ty!

 

[HarborFront]

D-Link Triple Play explained here

D-Link

dlinkmea.com

 

[Ink]

If you don't use the services, turn off the networking.

Chromecast and FireTV are decent low-cost dongles.