Is there a way to prioritize which wifi network your phone connects to by default when multiple are available?
Well that sucks! I have Comcast internet and so do multiple neighbors with the Xfinity hotspots enabled. I find our phones are connecting to these hotspots instead of my secure home network.
I had that same problem with the hotspots from my provider. I simply did the 'Forget this network' option for the hotspots and haven't enabled it since. Back in the day I had a cellular data plan with 6GB and even then I had no use for those 'hotspots'. Since last January I'm on an unlimited data plan and have definitely no need for it.
Surely it's up to you, but I'd delete it if it inconveniences you that much.
I myself have found that those hotspots are never really that great anyway.
Charter has started installing hot spots in my city. Some of my neighbors have them installed so as long as I use my Charter credentials, I can connected to any of them throughout the town.
Back to the OP, nope, can't be done.
That's different than how my provider does it.
Their modems have a built in guest network, completely sandboxed and separated from the client part. It has its own IP and also works with login credentials.
If I understand it correctly, Charter installs their hotspots separately in street lanterns or something similar?