Chip no longer accessible after first successful connection and flash attempt

Question

I'm having trouble with an MDBT42T-P192K (nRF52805) module and would appreciate any suggestions. 
 This is the sequence of events: 
 
 I assembled my custom PCB and connected it to a J-Link programmer. 
 Initially, everything appeared to work. nRF Connect Programmer was able to detect the device as an nRF52805, so I had communication with the chip. 
 I then flashed my Zephyr application from VS Code (nRF Connect SDK). The flash process appeared to start, but after that I completely lost communication with the module. 
 
 Since then: 
 
 nRF Connect Programmer cannot detect the device anymore. 
 nrfutil and west flash also fail because they cannot communicate with the target. 
 SWD communication is physically present. I can see activity on SWDCLK and SWDIO with an oscilloscope when the programmer attempts to connect. 
 The module is powered with 3.0 V. 
 nRESET is high when idle. 
 The wiring between the J-Link and the target has been checked multiple times. 
 I have also tried reset, erase operations available in Programmer, and reconnecting the hardware, but the behavior remains unchanged. 
 
 The important point is that the module was definitely reachable before the first flash attempt. After that single flash, I have been unable to establish any communication with it. 
 Has anyone experienced similar behavior with an nRF52805 or MDBT42T-P192K? I'm mainly interested in understanding what could cause a target that was initially detected to become completely inaccessible immediately after the first programming attempt. 
 (after chatting with the forum AI, good thing actually!, 
 it recommended that I first use nrfutil device recover. So that is what I've tried, still no success. Here is log: PS C:\Users\danne\blinky> nrfutil device recover --serial-number 1050399544 >> x Failed to recover 1050399544, Device error: Setting the debug port SELECT register failed while powering up sys and debug regions (Unknown error in the JError: One or more recover tasks failed: * 1050399544: Device error: Setting the debug port SELECT register failed while powering up sys and debug regions (Unknown error in the J-Link DLL (error code =-1)). This might indicate that the debug port is unavailable. Double-check device power supply and SWD lines, and ensure that SWD is not disabled (Generic) 
 ) 
 Below is the Schematic