Have struggled with brushless motor ESC programming and made up a small "flylead" to make it easier.
I always run on a separate Rx power supply,
so remove the red ESC power wire anyway. Rather that cut this off, now remove the plug entirely and bend the disconnected red wire back into the loom. Slide a piece of heatshrink over the loom, holding the red wire back.
Fit the heatshrink so the tip of the connector just protrudes from heatshrink. Shrink the heatshrink in place and refit the two plug wires.
Using a piece of scrap connector wire make up a fly lead that can be fitted into the plug and also into the end of the red wire.
The plug can be fitted into a programming card to make adjustments. The flylead is easily removed and the plug refitted to the Rx when complete.
This has the advantage of not wearing the plug slots and is quick to use.