My Samsung Galaxy Note II has been left behind.
  * Samsung/T-Mobile offer no updates, I’m stuck at 4.2.
  * T-Mobile has increased coverage,
        but my phone doesn’t reach their new channels.
  * The new thermostat I’m working with requires 4.5,
        so I have to use my wife’s to control it.
  * The new version of weatherunderground.com
        doesn’t work on what I’ve got, and it’s got
        all the local amateur weather stations.

I think 5-1/2 years is pretty good for a phone, but it burns me being abandoned like that.

Before I cave in and buy a new phone, since I’m letting go of this phone as it is, . . .
. . . is it time to root it, and install a new ROM that knows the Brave New World?

I see these:

    https://www.youtube.com/watch?v=cEkN919cHpk

    https://forum.xda-developers.com/galaxy-note-2/general/4-5-6a-t3269950

Is this a possible solution for me?
… and if I did do this, could I later convert it to operate as just a WIFI device as I moved on with a new phone?

There is no way I’d take on this job myself, with all that talent out in LinuxLand.
I *would* trust (and pay) a consultant who has done this kind of thing repeatedly, without recent bricking events.

Please advise . . .

Thanks,
Victor Odhner