Thanks for the warm welcome!
After posting, I did some more research (please correct me if I’m wrong) — it seems that all I really need is a SWD/JLink programmer and to connect the VCC, GND, SWDIO, and SWDCLK pins. I’ve just ordered a JLink v9, so fingers crossed it works when it arrives.
“If you plug in the USB, does the computer detect it with the USB new device Ding?”
No — that’s actually what made me suspect the board didn’t come with a bootloader in the first place.
“Are you able to enter BL mode (fast double reset push)?”
Unfortunately, I didn’t include a physical reset button on the PCB. Definitely something I’ll add in the next revision.
As for the Production BIN file or drag-and-drop UF2 testing — I assume those wouldn’t work unless the board is already being detected over USB, right?
Appreciate all the tips! Looking forward to getting the JLink hooked up and seeing if I can bring this board to life.