The Windows Insider team was able to find a temporary workaround for the issue!
I had already tried running WSRESET command without success, but they asked me to run this command:
wsreset -i
This opened a terminal window for a few moments, which then closed. At first it appeared it also was unsuccessful and the Store was still not found. However after about 2-3 minutes later, with no actual indication that any process was underway, the Store spontaneously opened up. From there I was also able to acquire the feedback hub.
They warned me that this is a per-user workaround, so it won't help other accounts on the same machine. It also has the side effect that the Store is unable to be updated so I'm stuck with an older version of the Store. However, at least it works!
I do not know what the -i command does, and wsreset /? does not yield any answers (I tried), but for now I'm at least able to install my many Store apps and participate in the feedback of Windows 11.