Not sure about the PS5.
Can you login to your Plex account on the TV and access the server, or is the problem with playing media?
If you are having trouble accessing the Plex server:
If your Samsung runs Tizen, you may need to adjust both server and TV app settings to allow insecure communications.
See: Important information about Plex for smart TVs after September 30, 2021
If your Samsung is an older model, see Old Samsung TV no link codes .
Basically, the TV too old. The article lists a work-around. However, you may be better served by using a streaming device such as Roku, Amazon, etc.
