Yes, I used MCUBoot and FOTA but didn’t go through the tests. I was hoping the '54L15 would make that easier 
I just used Segger’s Ozone for testing and debugging.
With the XIAO NRF54L15’s (when they arrive) I’ll use OpenOCD and GDB in VSCode.
I prefer the 'MG24 for all things Zigbee, Matter. Openthread, and BLE/Mesh.