I have the Toshiba model 65L5400U and after having it turned on for 30-40 minutes the toshiba remote will stop working completely, but my Roku remote will still work as far as pausing and fast forwarding it’s just the volume part that quits working.
Assuming that the remote works but not after 30 minutes and that you tried new batteries. I would say that the problems is in the TV.
If it's under warranty contact Toshiba.
If not then you can try
They sell replacement boards and are very helpful
The Roku remote only operated the Roku not the TV.