As far as I was able to test, User B does not have the possibility to change either the name or the color of the calendar shared with him within the his app context.

As you can see, User B now has two "Personal" blue calendar. This makes it challenging to differentiate on the calendar views.

Possibly, calendar colors should be limited to each user context making customizing colors personal whether for your own calendar or for calendar shared with you.

Ideally, and since I think that in some occasion having a unified calendar color for all having access to given shared calendar might be relevant too, this could also be a "flag"/tick box to select when sharing a calendar. something like "enforce coloring"

Hopefully this makes sense also.