Just drop the landline service

Does TrueNAS Scale suddenly not run dockers?

The UPS should “turn on” when plugged-in, even without a battery

Did you try to brain dead reset the device?

You need more RAM

If you can’t put in enough RAM to get the performance you want, then you need faster drives

I wouldn’t suggest paying for the upgrade solely for the backup cell Internet

And, to be honest, if you looked into it, you’d probably find it to be cheaper to roll your own entire system rather than dump money into a closed ecosystem

OP clearly isn’t looking hard… I have a line with 3GB a month of 5G data (plus unlimited throttled after that) for $15

Best solution: Build/buy a NAS and connect over your network

Second best choice: Stop using a NUC and get a computer with the necessary space for the hardware that you want to use