I’m on my 15 so I don’t have time to list everything but a lot of your assumptions are wrong about what you’d have to learn/ need to set up on your own. Synology has a suite of apps for all your use cases that makes it quite easy to set up. And there’s apps for your phone (yes android) to connect to it from outside of your network.
A good weekend of shmedium effort and you can have it all set up and running no problem.
If your powers unreliable btw you should invest in a battery backup UPS to protect sensitive products.
What browser would you recommend then?