Tried EVERYTHING!

My Corsa was running fine one day then on the evening the battery light came on & head lights were flickering at idle and under revs. This was followed by the "spanner" light... Then a few seconds later the EPS light- causing no power steering... airbag light all came on too. Under revs the lights extinguished and ran fine.
Alternator was brand new 12 months ago & has done 3k since then.
Overnight the battery on the car drained itself completely so, in case it was a dead cell or something.. I put a brand new battery on it last night & it failed to turn the engine to start.
I bump started it.. Moved it forward 10 ft & all dash board lights went out & wipers started going at high speed WITHOUT being turned on. I opened the drivers door at the same time & the drivers headlight flashed 10x brighter and blew a bulb & fuse.
Turned the car off & the battery was a lot warmer than it should be.
I've unplugged & plugged every socket & plug in I could find. Lubed every electrical connection I could find and still the same.
In car fault diagnostic showed a P0380 code Glow plug relay fault. Checked all wires and new plugs hence no code anymore.
I don't wanna use the car via bumping or jumpstart in case a major event occurs like an airbag going off or an engine fire. But I can't seem to find the source of the problem.