It's a known problem.
You go into a bar. Standing in the doorway, you say, loudly, "Hey, Mike!" 22 people named "Mike" turn around and stare at you for more information. You, lacking Mike Murphy's last name, say, "Hey, Mike!", again to 22 angry Mikes who all try to answer you at the same time in a mass confusion as they are all Mike. Everyone is lost as you can't talk to 22 people simultaneously. That's what Comcast has done to crash wifi across America. Every Comcast wifi hotspot has the SAME EXACT SSID, "xfinitywifi".
So, your stupid Windows/IOS/Android/Apple computer calls to connect to "xfinitywifi". At my local Waffle House, 15 of them all answer my call SIMULTANEOUSLY and, usually, nothing even connects. If one does connect, in the off chance one is a little stronger than the rest, the first time you send data to it, they all start calling and calling trying to reconnect. We sit with a professional networking program and joke about how stupid this is from this giant communications company that should, but doesn't, know better. Unless you can get close enough to ONE xfinitywifi that obliterates the signals from all the other xfinitywifi stations on the channel (1 or 6, sometimes 11), it WON'T WORK! As usual, when trying to describe this to tech support who know how to configure cable boxes but have no idea how 802.11(x) wifi operates, trying to get the Comcast beast to CHANGE the SSIDs to something UNIQUE, such as "xfinitywifi + the last 4 hex characters of that modem's MAC address" is like trying to push a 2500 pound elephant up a hill. Every hotspot having the same SSID must be ok or the Comcast beast wouldn't have done it. So, expect wireless wifi in every Comcast city in America to become a nightmare of stations all with the same SSID crashing and crashing and trashing wifi for everyone, not just Comcast's inop customers unless FCC does its job.
Starbuck's can pull it off because although they're everywhere, there generally aren't more than three per block. On the other hand, the birth center backs up against a 22-unit apartment building and unless you buy your own modem, every single Comcast customer is bleeding out "xfinitywifi" giving your phone around 11 SSIDs with the same name.
I can watch the "xfinitywifi" signal jump 20dB as my phone chooses between three or four of them.
Project Fi only works with Google or Nexus-branded phones because only Google or Nexus-branded phones will run dual-band on a single SIM. Your choices are 5X, 6, 6P, Pixel or Pixel XL.
Also, if your router is running damn near any kind of security, it'll take an extra second or two over barely-secure xfinitywifi. My laptop does it often, even though I'm less than five feet away from a rock-solid Netgear Nighthawk. It's the security.