I use the Nissan Connect EV app regularly with my 2018 SL. Unfortunately, the reviews are pretty accurate. I have an iPhone so I can only comment on the iOS version. I have found it works fairly well sending instructions TO the car, like start charging, start/stop climate control and lock/unlock doors. It has only failed once in the few months I've been using it. Getting feedback FROM the car has not been reliable at all. Most status updates require multiple "refreshes", each taking 30-60 seconds. With enough patience, the app does eventually update. It also doesn't seem to matter if the car is parked in a garage or out in the open so it doesn't appear to be a signal issue.
2018 Leaf SL, 19,202 km, SOH - 94.35%, Hx - 121.02, 108.918 AHr