My recipe DIY mains cable:
4x2 (8 wires)twisted solid stranded ofc copper wire (have to lookup the wire-gauge)with teflon, foil and copper-mesh shielding, teflon tape, nice cotton outside.
No soldering Furutech connectors, they are expensive but VERY nice contact clamps and high contact strenght.
Look very nice, works very well.
This way its also very easy to test different cable designs, without soldering.
Never touch contact points with your fingers, clean them with pure alcohol, btw. alcohol removes soldering flux too.
my 2 (euro) c