My network is configured the same way. I live in a town home and the WiFi is CONGESTED! There is someone in the neighborhood blasting out WiFi and is causing issues. I'm going to have to keep an eye out and see who is walking around with a second head. Once it connected, it's been fine. It kept telling me my phone was connected to 5ghz even though my phone specifically said it was 2.4. I have a feeling the people that are really complaining are people that are a bit less tech savvy. However, at a price point this high; it needs to be way better. I've been in IT for 12 years and it still took some fiddling from me. I went so far as to set up a guest network under 2.4 only with an SSID of dosers and hid the network just incase I couldn't get connected on my standard SSID.
The calibration is where the real issue is with me. I go into the calibration screen. I leave it at 350rpm and make sure it's primed. I set it to dispense for 10s and then enter the volume dispensed. The first issue is that hitting the calibration complete button doesn't always work. I can select other items on the screen but this button doesn't seem to notice my finger press. It's probably a 50% chance of it working. Once I'm done calibrating, I go back and do a manual add and choose 10mL. I almost never get 10mL and always more. I've uninstalled the app twice and also reset the pump back to factory. I'm finally at about 11mL when dispensing 10mL it's dosing Kalk on a plan and seems to be working good enough. If I were dosing nitrates, phosphates, or anything else that would need to be a bit more precise. I'd have a real problem with it.
Edit: I'm on a Google Pixel running the latest Android.