as programmer i use nrf53dk or JLINK edu mini.
I don’t see a nRF53, for me this looks like a nRf9160-DK.
Also i tested this programmer configuration with thingy91 ant it works.
Please be careful, as the Thingy:91 uses a 1.8V for VDD IO (and so the nRF9160-DK must be switched (SW9) to use 1.8V as well), but the feather uses 3.3V VDD IO (and so the nRF9160-DK must be switched (SW9) to use 3.0V).
using a tag connect TC2030-CTX-NL
Considering, that at least others time is also money, the 60* $ for that connector isn’t that much . If you’re not located in the US, some resellers (e.g. digikey) may help. You may also order one “with Legs” (TC2030-CTX, the NL is for No Legs) and cut the legs off.
(* 60$ the price seems to have been raised. Maybe a reason to switch in the future to the 10 pin headers.)
