Well, after restarting, it tried to acquire Sprint DM again (I guess it had gotten stuck), now I get a diff msg when dialing out (we are unable to complete your call at this time)... I am able to dial in and answer the call.
EID: bunch of #s
Cached Subscription: bunch of #'s
UICC subscription: bunch of #'s... same as cached
SIM operator: Unknown [It was giving me a bunch of invalid SIM messages during this enhance coverage activation process]
Network operator: Sprint
Looks like it failed to activate under Sprint (because I have bad Sprint coverage here)... so I had to go to Settings, Apps & Notifications, App Info, Google Fi, Storage, and Clear Data/Cache. Then redo activation then redo Maxiize Coverage.
Now it's using T-Mobile towers since that's the strongest signal for me.