Tapping into a 4 AWG wire
That's a problem I have faced too and I solder taps and coat with polyurethane sealant (hardware store tube) for outdoor 10W LEDs along fence.

I have used 3mm bolt/nuts and crimp lugs for &lt;5mohm on interior chassis instead of a paint masked welded grounded lugs with star washers which got UL approval.

IDC connectors are hard to find and not reliable outdoors.

Zinc plated steel and copper straps will get galvanic corrosion eventually unless air tight seal (polyurethane).  What about brass screws?

I use to test with 10A load and measure voltage drop to measure initial resistance of contact.

Corrosion is inevitable and depends on climate.

i think self tapping screws with self-tapping washer? (or piece of 1/8th FR4 with a hole  to act as a compression nut, then grind off tip and air tight seal.

Automotive uses water tight connectors for headlamps etc. which are good for servicing loads.

Let me know what you end up with.. I use AWG16 solid round copper, but your cable is better but braid will stretch and screw pressure will relax braid and force air in, which is why I suggested compression nut to self tapping screw. Robertson style. with crimp or solder lug of suitable shortest length,screw.  unless you have a better way less labour intensive.