OK... so after much more digging around in this and other various forums, it seems like I'm not the only one having this same problem. And it seems like this is an issue specific to the Pi Zero W and Android phones (SSH timeout).
There's this one...
Nothing useful there as it seems that issue is still unresolved after 3 years
And this one...
Nothing useful here as it is a slightly different issue from the one I am having. Although I did try the edits to the sshd_config and it did not fix my problem
And this one...
Setting a different SSH port didn't work either
I am able to connect to the Pi from my laptop via the WiFi using a static IP and I can SSH into the Pi.
I can ping the Pi to itself (10.0.0.1) and it works ok.
I can ping my phone from the Pi (10.0.0.10) and that works ok.
I can ping my laptop from the Pi (10.0.0.5) and that works ok.
I can NOT ping the Pi from my phone even though my phone says it is connected to the Pi with IP address 10.0.0.10, and I can not SSH into the Pi from my phone no matter what app I am using... I get the same error: Connection error. Timeout. Socket is not established.
I am still hoping someone can give me an answer as to why this isn't working... at least someplace I should be looking for where the problem might be... some configuration file on the Pi... SSH config? Networking config? Anything? Bueller.... Bueller? I've been working on this project for 2 months now, trying to get it working before our monsoon season here in Arizona so I can shoot some nice time lapse movies of the rain storms, clouds, and awesome sunsets... and I thought I finally had everything working, only to be stopped dead by this problem. I really need to find a fix for this, the whole point of building this camera was to be able to use it out in the field and connect to it via my Android phone so I can adjust the settings on the time lapse and stepper motor scripts via SSH. Hiking my laptop into the wilderness in my backpack is not an option, the camera and my phone are small, light, and weather proof... my laptop is not
Would really appreciate some help getting this to work like it's supposed to.