A weak power supply is sometimes suspected when you get buffering during playback, it’s not able to provide enough power (amps) to the hard drive (at least that’s the theory).
So I was thinking that maybe the same thing could be true for the Wi-Fi dropouts. If you get a new power supply and it doesn’t change the issue, then you have a spare. Some on this forum have bought generic power supplies from Amazon.
Here’s the link to the thread where the Amazon power supply was mentioned.