Since this is incorporated in the power cord I wonder if irregularities in the power running through it (surges, spikes, etc.) could be the source of your troubles. My Streaming Stick+ is powered through a computer grade surge protector, same as the tv, and in the year+ I've had it I've never had a problem with the wifi receiver.
Roku Community Streaming Expert
I am not a Roku employee, only a user like you. Please, no support questions via private message -- post them publicly to the Community where others may benefit as well.
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Streaming Stick 4K+ 3821 | Streaming Stick+ 3810 | TCL Roku TV 43S245/C107X