Voltage issue - Hoping for some guidance

Hello All, hoping you guys can point me in the correct direction.
16 Base 3.6 with about 100k on it

On Saturday, -15 degrees Fahrenheit outside my wife starts the truck up, no dash lights at all, whole interior is dead
Truck runs and drives fine
Getting code U0155 - Lost Communication with Instrument Panel Cluster
No fuses are blown
Radio Works

Truck sits until Tuesday, ran it for a while and dash started to come alive. Drove it for about 30 miles and whole dash was going crazy. Multiple systems coming on and off so appears to be a voltage issue that's not specific to the cluster.

I put a battery in it yesterday thinking that may be all it is. Battery fixed the issue for about ten minutes then back to the same crazy dash
Old battery tested fine so the ten minutes of no issues doesn't make sense to me

This morning it will barely even run

I'm thinking alternator is on its way out but wanted some qualified opinions before I start tearing into it. The truck should be able to run off a brand new battery for more than ten minutes. I'[m aware there is a battery reset function that I'll need the dealer or another shop to reset for me but I dont think that would cause the issues I'm having since the battery wasn't the issue in the first place

I appreciate the help