Grounded outlet.
No one practices golf in the yard.
Don't watch porn on it?
Lol
You can always spend 20/30 K to enclose the deck around your "cheap" TV. ROKU sounds like something from a Jules Vern novel. But that is the ticket, 30/40 K to build a new deck to get outdoors and at the same time enclose the current deck to protect ROKU. That is the reasonable approach to this entire situation or move "game time" to the garage along with the deck appliances and sun in the drive. That way the current deck and newly attached deck can be turned into another bedroom for the viewing family and friends. Add 10K for the remodel to plug in a bathroom for them also. For a lousey 50K the problems are taken care of, game watching can continue, beer drinking can forge ahead, and let it rain, on the reflection. Happy to have been of help and feel free to ask any related questions I may be of help with. Gooo for the gusto, Grampa.