Thanks. That does clarify a few things, especially on the reset/reboot. So far in my recent round, the doorbell only went offline once after an intentional power reconfigure, and a reboot through the web portal and a delete/add at the hik-connect URL someone gave earlier (not any app) was all it took to get me back on track. No factory restore.
I certainly understand and agree with the "if it ain't broke, don't fix it".
I think I'm good on the WiFi level. My new location for the access point is actually farther away from the doorbell, but it's now in a normally unoccupied room and I can crank up the 2.4 GHz power level for that AP a bit to give the doorbell a stronger signal without overpowering other active WiFi devices in the area. What I remember reading when setting up my Ubiquiti stuff is that some devices start going into saturation over about -45 dBm, so going stronger may not always be better for all devices. I'll pay more attention to this as I progress to adding the doorbell to the NVR, etc. I do know that my Ubiquiti/Unifi controller is reporting excellent signal strength on what it is receiving back from the doorbell.
I haven't explored the NVR apps much yet, so thanks for the reference to the ADT one. So far I've been exposed to two - Lechange and MontavueGo. Lechange came about as a natural part of the install. I think the NVR prompted me to install EasyIP, which has apparently been replaced by Lechange. My NVR is a Monatvue rebadge, and the documentation referenced MontavueGo. I'm sure that's just a copy of some Dahua app, but I haven't dug into it yet. I don't record anything 24/7 - everything right now is event driven. As best I can tell, with Lechange app notifications to the phone are an all or none. It either reports all the events the NVR triggered on or I can get none of them. Also, something between Lechange, T-Mobile and our LG phones keeps us from being able to reliably look at live view or recordings when on the cell network, which is a big hindrance. I haven't spent any time trying to fix that. I have found MontavueGo is more reliable at being able to view things on the cell network and it gives me the option to pick and choose the channels I want to receive notifications from, even though the NVR is still recording all events. That's a step in the right direction for me, but I find it to be more cumbersome to use than Lechange. I'm mostly interested in figuring out the best "viewer" app for the NVR. Configuration changes and such I'll likely keep doing right at the NVR keyboard/monitor, at least for now.
Edit: A correction on the WiFi level. What I think I remember reading is that the "sweet spot" for most devices is between -45 dBm and -55 dBm, not that devices risk going into saturation at -45 dBm.