Ya the server route is super useful, i did away with using the cheap Chinese cables.. had to many run super warm due to loose connections, not looking for another melted connector event to occur.... i have gone to soldering everything except for the ends that plug into the GPU's, i bought a bulk amount of pcie connectors and pins for those connections and i solder each pin on instead of just crimping them on... my last build i did, i used breakout boards that i soldered the wires to the pins on the breakout board and ran the wires to wiring blocks, then to all the connections, even ran the extra 12v computer fans off the 12v power of the server psu that route for a while. ever since i switch to securing everything better, i have had way way less issues using the risers now.. between using strips of wood clamping the gpu to the riser and hot glue on every connection.. the random lockups and restarts kinda went away.
If you're not flexing the cables a lot, crimp + solder is a GOOD idea.
If you ARE flexing the cables a lot, the solder will tend to break eventually and can cause issues, but that should not be the case in a GPU rig - we're talking typically many thousands of lifetime flexes, not a dozen or less for install + occasional troubleshooting.