This is the app I used with my S5:
https://play.google.com/store/apps/details?id=ir.tv.remote.control.samcontrol
The app isn't compatible with my S9+ but the developer has a similar looking app:
https://play.google.com/store/apps/details?id=smart.tv.wifi.remote.control.samcontrol
Trouble is, neither that nor any other app I can find similarly work using my new phone? The TV is also Samsung, but it's not a Smart TV. It can connect to the internet but only through our Telus Optik box. Does anyone know what might be wrong or if it's possible to continue using my phone as a remote with this newer Galaxy model?
Read more: https://samsungus.org/qa/s9/my-samsung-galaxy-s5-works-as-a-tv-remote-but-not-my.html