CAT 287C (MAS) No Start, No Charge, Right Joystick Dead + Warning Lights

I’m having a complex electrical issue with a Caterpillar 287C (Serial: CAT0287CHMAS01365). Symptoms: No Start: Turning the key turns the machine on, then nothing, no signal to starter. The safety switch light on the dash for the arm bar goes on and off when lowered and raised so the safety switch seems to working appropriately. Prior to this most recent no crank issue, when the machine would sit for a week the battery would be dead, as if there was a slow draw somewhere. I cannot for the life of me trace the signal wire to any relay or the ECM, it goes into a bundle of wire and disappears, Im not sure if it goes to a relay or ECM. There is only AC in the cab, no heat, maybe a mixing valve? Workaround: If I jump power from the battery directly to the starter signal wire with the key 'ON,' the machine starts and runs. Secondary Issues: Once running, the alternator is not charging (battery light on and off in the cab). The right joystick (lift/tilt) does not function at all. Dash Lights: I have a flashing exclamation point and the hydraulic warning light is on. Drive: The machine will move forward and backward using the left joystick, but that's it. What I've Checked: Starter pulled and bench-tested (Functioning fine). Ignition switch pulled and replaced, no change in any function. Safety armbar switch seems to be functioning fine as the dash light goes out. Checked all fuses/relays in the cab and under the cab they seem to be fine. Cleaned grounding connections and power connections. I do not see fuses/relays in the engine bay. It feels like a 'Main Power' or 'ECM Power' issue since it affects multiple unrelated systems (Charging, Starting, and Hydraulics). Has anyone seen this on a C-series before? Is there a hidden main ground or a specific interlock relay I’m missing? Thanks for reading this and let me know any advice you may have.