Djozz did some interesting work re. springs here:
I use the Fasttech ‘carobronze’ springs to avoid the need for a wire bypass.
Not the best, but much better than steel springs and does not heat up at moderate-high currents.
https://www.fasttech.com/product/1347100-batterydriver-contact-support-spring-for-flashligh
Big issue with the A6 drivers is probably the off-time cap and related firmware. The short/medium/long press duration all gets stretched as driver board heats up. Build quality may also not be consistent. I tried a few and they are OK, but this is with my own firmware and not using the OTC. One pleasant surprise was that the stock wires are silicone-insulated and the spring is non-magnetic (so not steel).
Anyone knows what metal is used for the springs on these drivers?