AnalogLamb ESP32 Programmer with CH340 USB to Serial Chip – analoglamb.com
MTA6 – RS Components 543-7750 (requires assembly tool – any 2.54mm SIL connector will do if you already have alternative tooling)
7/0.2mm² cable – RS Components 214-0661
15.9mm Clear heatshrink – RS Components 873-9191
Assembled programming adapter
Ensure you cut away the heatshrink over the "EN" button so it isn't permanently pressed down.
Use a permanent black marker to mark pin 1 on the connector so its obvious when plugging onto the PCB header.