I am now back home and no longer traveling. I am going to test things and report back; however, I notice that now the same apps that were not functioning before because they wanted to only use cellular are functioning as normal and using wireless.
What I wonder then is why did my particular location or wifi router(?) make such a difference in the place I was traveling to? Why would the device not simply recognize wifi as wifi, with priority, regardless of location?
Thank you.
Donāt get me wrong. The second command probably only becomes essential if /etc/resolv.conf gives you 127.0.0.53
Right now on my Librem 5 (presumably reflective of most peopleās phones) /etc/resolv.conf does contain the actual DNS server IP address.
So if I start off with WiFi on and cellular on (via HKS) then this file gives me my LANās DNS server IP address. If I then kill WiFi then this file gives me the DNS server IP address associated with the mobile service. If I then turn WiFi back on then this file goes back to giving me my LANās DNS server IP address.
So the command that you gave is fine on my Librem 5. However I guarantee you that it would not work on my desktop or on my server (which would always just show 127.0.0.53).
Note though that DNS is only one piece of the puzzle. Routing and application behaviour are two other pieces of the puzzle.
Gotta agreeā¦ mostly. Just before starting this reply, I see it is using cellular data. However, when cycling HKS WIFI only and again checking, I find it using WIFI. Did it honor the priority or just grab the new thing? 
I am always interested to see how people solve problemsā¦ lots of ways to skin a rabbit.
When I want to where my data is coming from, I use Speedtest CLI. Default output shows provider as well as test server and stats.