I have an Pi 4 that I have setup as a router. I am using USB-C in Ethernet gadget mode to connect to my computer. I want to be able to disconnect and reconnect the Pi from my computer without it shutting down. For this I need external power. This is no problem as I can feed 5V via the GPIO header, and have made an adapter for this purpose. But I am concerned that plugging my Pi 4 into my computer via the USB-C port while it's powered up via external power will harm the Pi, or worse, my laptop. Any suggestions?
I can cut the power trace on the Pi board, which would be a good solution for me, but I don't know if USB-C will continue to work if I do that. Also, I don't know if the Power trace is accessible.