I've gotten to the point where I'll manually turn off WiFi as soon as I set foot outside my front door. It should be automatic.
https://www.howtogeek.com/129728/how-to-access-the-developer...
you then have the option to enable "Aggressive Wi-Fi to Cellular handover"
> It just artificially reduces the WiFi RSSI (received signal strength indication) to encourage the WiFi state machine to decide to switch the connection from WiFi to cellular network.
https://android.stackexchange.com/questions/90250/what-does-...
Anecdotally, I have had fewer headaches with the phone holding on to poor wifi-signals since I enabled this. Ideally the phone would handle this in a smarter way, e.g., by monitoring the strength of both the wifi and data signals and switching to whichever is likely to have the least packet loss.
The tradeoff here of course is battery life. The phone OS doesn't want to switch on a second radio until absolutely necessary for obvious reasons.
My intuition for whether a request that's not done yet is ever going to complete seems to be much better than what's written into most apps. It's really annoying when I have to entirely kill and reopen the app, rather than just have that one operation retried.
The main culprit here is of course TCP's session based view of the world which was invented for a completely different era. An era when "cable got cut" was a catastrophic event that was almost never going to happen. It's a pity that the native app world is still mostly stuck with TCP/HTTP based networking stack where a UDP/mobile-specific-protocol is what's needed.